<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:1a7990cb-3a72-413a-8423-f20e24f4f1ad,g:4ca54b38-6823-4da2-9e99-378b377d8a6e-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.quakerchem.com/role/CondensedConsolidatedStatementsofChangesinEquity" xlink:type="simple" xlink:href="kwr-20240930.xsd#CondensedConsolidatedStatementsofChangesinEquity"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/CondensedConsolidatedStatementsofChangesinEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_25f5f44f-036a-4f51-a0bb-bc76ba863f52" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_639c80cb-c22e-4f69-841e-5e35b2b59582" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_25f5f44f-036a-4f51-a0bb-bc76ba863f52" xlink:to="loc_us-gaap_StatementTable_639c80cb-c22e-4f69-841e-5e35b2b59582" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_30d234b3-a188-49c7-a4d3-f5a167c6ba23" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_639c80cb-c22e-4f69-841e-5e35b2b59582" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_30d234b3-a188-49c7-a4d3-f5a167c6ba23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_30d234b3-a188-49c7-a4d3-f5a167c6ba23_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_30d234b3-a188-49c7-a4d3-f5a167c6ba23" xlink:to="loc_us-gaap_EquityComponentDomain_30d234b3-a188-49c7-a4d3-f5a167c6ba23_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_30d234b3-a188-49c7-a4d3-f5a167c6ba23" xlink:to="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_a727c019-b486-44f4-b1c5-275980a7c531" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:to="loc_us-gaap_CommonStockMember_a727c019-b486-44f4-b1c5-275980a7c531" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_ea885877-61d3-45de-aabe-15dd0cd30571" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_ea885877-61d3-45de-aabe-15dd0cd30571" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_dae61e22-a88d-4ef3-94df-a526ee5db48b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:to="loc_us-gaap_RetainedEarningsMember_dae61e22-a88d-4ef3-94df-a526ee5db48b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_23dfa913-0b11-4eba-9e25-c8a0800d2db8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_23dfa913-0b11-4eba-9e25-c8a0800d2db8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_143c8f28-0b34-4f3f-9b14-452e6dd1c278" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0231ce69-b8c9-4d73-82a8-5ca2c36c893c" xlink:to="loc_us-gaap_NoncontrollingInterestMember_143c8f28-0b34-4f3f-9b14-452e6dd1c278" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_25f5f44f-036a-4f51-a0bb-bc76ba863f52" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_082b9db6-e80b-4de8-a50b-f395d81d42fd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_082b9db6-e80b-4de8-a50b-f395d81d42fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_19bd86ab-1d20-4535-854b-e1d3904739dc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_us-gaap_ProfitLoss_19bd86ab-1d20-4535-854b-e1d3904739dc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_5d6b2bda-90a0-40cd-8c18-248c56a6a4df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_5d6b2bda-90a0-40cd-8c18-248c56a6a4df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_f7c8bb4e-a799-481c-b03d-2b82de1d2a40" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_us-gaap_DividendsCommonStock_f7c8bb4e-a799-481c-b03d-2b82de1d2a40" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_5973b306-dd89-4815-aa2b-d47090cc304f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_5973b306-dd89-4815-aa2b-d47090cc304f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_StockRepurchasedAndRetiredDuringPeriodExciseTaxValue_e3336cbc-6126-40b4-ba75-67ab19eadc17" xlink:href="kwr-20240930.xsd#kwr_StockRepurchasedAndRetiredDuringPeriodExciseTaxValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_kwr_StockRepurchasedAndRetiredDuringPeriodExciseTaxValue_e3336cbc-6126-40b4-ba75-67ab19eadc17" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross_e6d59572-cfdb-4888-a283-87560111110c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c6d31b4f-d0be-40d7-9ca2-ac161fbde52d" xlink:to="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross_e6d59572-cfdb-4888-a283-87560111110c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_d3729a51-2a3e-4f4e-a5e8-770a8947a5f4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/BasisofPresentationandDescriptionofBusinessDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#BasisofPresentationandDescriptionofBusinessDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/BasisofPresentationandDescriptionofBusinessDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_a8d49afc-ce62-49e6-b38e-99448feab96c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_75865983-b601-4fec-b98d-a7f69e5f4873" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_a8d49afc-ce62-49e6-b38e-99448feab96c" xlink:to="loc_us-gaap_StatementTable_75865983-b601-4fec-b98d-a7f69e5f4873" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_6d0347c2-8177-4c85-8291-38447b3e1867" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_75865983-b601-4fec-b98d-a7f69e5f4873" xlink:to="loc_srt_ConsolidatedEntitiesAxis_6d0347c2-8177-4c85-8291-38447b3e1867" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_6d0347c2-8177-4c85-8291-38447b3e1867_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_6d0347c2-8177-4c85-8291-38447b3e1867" xlink:to="loc_srt_ConsolidatedEntitiesDomain_6d0347c2-8177-4c85-8291-38447b3e1867_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_4c00dd28-3496-4d3d-b4dc-323875bb1faa" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_6d0347c2-8177-4c85-8291-38447b3e1867" xlink:to="loc_srt_ConsolidatedEntitiesDomain_4c00dd28-3496-4d3d-b4dc-323875bb1faa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SubsidiariesMember_bf1d8994-ea43-4ad0-9047-c11fbb59cfa7" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_4c00dd28-3496-4d3d-b4dc-323875bb1faa" xlink:to="loc_srt_SubsidiariesMember_bf1d8994-ea43-4ad0-9047-c11fbb59cfa7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_588c6a12-68e8-44aa-8a6a-474eb004b21b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_75865983-b601-4fec-b98d-a7f69e5f4873" xlink:to="loc_srt_StatementGeographicalAxis_588c6a12-68e8-44aa-8a6a-474eb004b21b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_588c6a12-68e8-44aa-8a6a-474eb004b21b_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_588c6a12-68e8-44aa-8a6a-474eb004b21b" xlink:to="loc_srt_SegmentGeographicalDomain_588c6a12-68e8-44aa-8a6a-474eb004b21b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_228daf98-8f32-4d5b-9e39-19d252d7d87c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_588c6a12-68e8-44aa-8a6a-474eb004b21b" xlink:to="loc_srt_SegmentGeographicalDomain_228daf98-8f32-4d5b-9e39-19d252d7d87c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_ArgentineAndTurkishSubsidiariesMember_053a779c-7136-474c-9b93-c76e054911df" xlink:href="kwr-20240930.xsd#kwr_ArgentineAndTurkishSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_228daf98-8f32-4d5b-9e39-19d252d7d87c" xlink:to="loc_kwr_ArgentineAndTurkishSubsidiariesMember_053a779c-7136-474c-9b93-c76e054911df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_e535c4df-2ebd-431f-b6f6-8e88d36302ff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_75865983-b601-4fec-b98d-a7f69e5f4873" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_e535c4df-2ebd-431f-b6f6-8e88d36302ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_e535c4df-2ebd-431f-b6f6-8e88d36302ff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_e535c4df-2ebd-431f-b6f6-8e88d36302ff" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_e535c4df-2ebd-431f-b6f6-8e88d36302ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_318afce4-e34a-4d3e-949b-6cb16cf78310" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_e535c4df-2ebd-431f-b6f6-8e88d36302ff" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_318afce4-e34a-4d3e-949b-6cb16cf78310" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsTotalMember_9bcc04f8-7ed9-44ca-8e0e-430b5e79048a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsTotalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_318afce4-e34a-4d3e-949b-6cb16cf78310" xlink:to="loc_us-gaap_AssetsTotalMember_9bcc04f8-7ed9-44ca-8e0e-430b5e79048a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_aa3ac310-0176-4a46-9619-1b47677b0ece" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_318afce4-e34a-4d3e-949b-6cb16cf78310" xlink:to="loc_us-gaap_SalesRevenueNetMember_aa3ac310-0176-4a46-9619-1b47677b0ece" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_cfb55925-4958-4e00-b216-a30fb45e07ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_75865983-b601-4fec-b98d-a7f69e5f4873" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_cfb55925-4958-4e00-b216-a30fb45e07ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_cfb55925-4958-4e00-b216-a30fb45e07ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_cfb55925-4958-4e00-b216-a30fb45e07ab" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_cfb55925-4958-4e00-b216-a30fb45e07ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_9cc5ccfc-a166-4a89-a13f-6a9e02d36ba0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_cfb55925-4958-4e00-b216-a30fb45e07ab" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_9cc5ccfc-a166-4a89-a13f-6a9e02d36ba0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicConcentrationRiskMember_eaea655c-2499-4a62-958e-038f92fb8cae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeographicConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_9cc5ccfc-a166-4a89-a13f-6a9e02d36ba0" xlink:to="loc_us-gaap_GeographicConcentrationRiskMember_eaea655c-2499-4a62-958e-038f92fb8cae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_7380f397-ccac-4984-832d-a87f7053ad57" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a8d49afc-ce62-49e6-b38e-99448feab96c" xlink:to="loc_us-gaap_NumberOfReportableSegments_7380f397-ccac-4984-832d-a87f7053ad57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfCountriesInWhichEntityOperates_e66b1ac7-c3c0-4250-b1d1-1b60805c9cc9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NumberOfCountriesInWhichEntityOperates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a8d49afc-ce62-49e6-b38e-99448feab96c" xlink:to="loc_us-gaap_NumberOfCountriesInWhichEntityOperates_e66b1ac7-c3c0-4250-b1d1-1b60805c9cc9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_58558ebb-8bf7-411f-90dc-1654dfb1e476" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a8d49afc-ce62-49e6-b38e-99448feab96c" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_58558ebb-8bf7-411f-90dc-1654dfb1e476" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmountRecognizedInIncomeDueToInflationaryAccounting_f0c6d5ce-de34-4c2e-8aab-e8e62d218cc8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AmountRecognizedInIncomeDueToInflationaryAccounting"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a8d49afc-ce62-49e6-b38e-99448feab96c" xlink:to="loc_us-gaap_AmountRecognizedInIncomeDueToInflationaryAccounting_f0c6d5ce-de34-4c2e-8aab-e8e62d218cc8" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/BusinessAcquisitionsDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#BusinessAcquisitionsDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/BusinessAcquisitionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_59b28ad5-2fb2-40be-9f43-0585886f7021" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_59b28ad5-2fb2-40be-9f43-0585886f7021" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_e17db9aa-e9f2-4621-b19b-94e405f6c513" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_59b28ad5-2fb2-40be-9f43-0585886f7021" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_e17db9aa-e9f2-4621-b19b-94e405f6c513" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e17db9aa-e9f2-4621-b19b-94e405f6c513_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e17db9aa-e9f2-4621-b19b-94e405f6c513" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e17db9aa-e9f2-4621-b19b-94e405f6c513_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4bf26404-1dce-4b19-941f-b1110f95c317" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e17db9aa-e9f2-4621-b19b-94e405f6c513" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4bf26404-1dce-4b19-941f-b1110f95c317" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_SutaiGroupMember_c5dc2edf-1774-4fc8-96fd-f0f36482d741" xlink:href="kwr-20240930.xsd#kwr_SutaiGroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4bf26404-1dce-4b19-941f-b1110f95c317" xlink:to="loc_kwr_SutaiGroupMember_c5dc2edf-1774-4fc8-96fd-f0f36482d741" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_I.K.V.TribologieIKVTMember_84de84d2-8da1-4a1a-9d13-711fa094f40c" xlink:href="kwr-20240930.xsd#kwr_I.K.V.TribologieIKVTMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4bf26404-1dce-4b19-941f-b1110f95c317" xlink:to="loc_kwr_I.K.V.TribologieIKVTMember_84de84d2-8da1-4a1a-9d13-711fa094f40c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_cf9ef193-6854-48ca-8381-a750095f1003" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_59b28ad5-2fb2-40be-9f43-0585886f7021" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_cf9ef193-6854-48ca-8381-a750095f1003" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cf9ef193-6854-48ca-8381-a750095f1003_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_cf9ef193-6854-48ca-8381-a750095f1003" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cf9ef193-6854-48ca-8381-a750095f1003_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b8caa0ea-0087-4b99-aa81-f04a609bc39a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_cf9ef193-6854-48ca-8381-a750095f1003" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b8caa0ea-0087-4b99-aa81-f04a609bc39a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_81652cb5-7d01-4e77-bcef-5a1dc5b75328" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b8caa0ea-0087-4b99-aa81-f04a609bc39a" xlink:to="loc_us-gaap_CustomerRelationshipsMember_81652cb5-7d01-4e77-bcef-5a1dc5b75328" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_a6cb0e47-1de3-4784-b0da-7bb92521402d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TechnologyBasedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b8caa0ea-0087-4b99-aa81-f04a609bc39a" xlink:to="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_a6cb0e47-1de3-4784-b0da-7bb92521402d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_4befcd52-035d-4797-a734-9797c000c52c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b8caa0ea-0087-4b99-aa81-f04a609bc39a" xlink:to="loc_us-gaap_TrademarksMember_4befcd52-035d-4797-a734-9797c000c52c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_b3f8d423-6f70-40ad-b3e9-ff924bbdd3ef" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_b3f8d423-6f70-40ad-b3e9-ff924bbdd3ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_316ec946-9a1a-4058-b339-78afcacb8bb3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_316ec946-9a1a-4058-b339-78afcacb8bb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_EarnoutLiabilityAdjustment_1e08ca28-5816-45cd-8f3a-0cc190a71dc4" xlink:href="kwr-20240930.xsd#kwr_EarnoutLiabilityAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_kwr_EarnoutLiabilityAdjustment_1e08ca28-5816-45cd-8f3a-0cc190a71dc4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_30f17d80-be21-4ccd-8d1c-02dfbc452ba1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_30f17d80-be21-4ccd-8d1c-02dfbc452ba1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_55552d37-8384-43a9-947d-71d29179ce12" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_55552d37-8384-43a9-947d-71d29179ce12" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_d1309465-5ade-49e2-baac-141abef53012" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_Goodwill_d1309465-5ade-49e2-baac-141abef53012" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_0cb7003a-7ebf-47a5-a02b-4d723f8d3653" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_0cb7003a-7ebf-47a5-a02b-4d723f8d3653" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_ebf5de48-1bc7-48eb-80c6-02f095ef8059" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_7c3ed6bc-7e39-44f7-a2a8-dc9185e77995" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_ebf5de48-1bc7-48eb-80c6-02f095ef8059" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/BusinessSegmentsPerformanceofReportableSegmentsDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#BusinessSegmentsPerformanceofReportableSegmentsDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/BusinessSegmentsPerformanceofReportableSegmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_16d03381-9e4e-4cc7-89e3-c3ccb08e1f0b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_16d03381-9e4e-4cc7-89e3-c3ccb08e1f0b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_bebde580-6999-4cd8-81ff-182c6472ba15" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_16d03381-9e4e-4cc7-89e3-c3ccb08e1f0b" xlink:to="loc_srt_ConsolidationItemsAxis_bebde580-6999-4cd8-81ff-182c6472ba15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_bebde580-6999-4cd8-81ff-182c6472ba15_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_bebde580-6999-4cd8-81ff-182c6472ba15" xlink:to="loc_srt_ConsolidationItemsDomain_bebde580-6999-4cd8-81ff-182c6472ba15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_bd007b75-2b54-4420-8fc0-3df083baaa7e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_bebde580-6999-4cd8-81ff-182c6472ba15" xlink:to="loc_srt_ConsolidationItemsDomain_bd007b75-2b54-4420-8fc0-3df083baaa7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_e1bf5943-76d0-4eaa-a805-c4f415acaea7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_bd007b75-2b54-4420-8fc0-3df083baaa7e" xlink:to="loc_us-gaap_OperatingSegmentsMember_e1bf5943-76d0-4eaa-a805-c4f415acaea7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_98b5cbfe-d6b2-4413-8849-91d3a4262534" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_bd007b75-2b54-4420-8fc0-3df083baaa7e" xlink:to="loc_us-gaap_IntersegmentEliminationMember_98b5cbfe-d6b2-4413-8849-91d3a4262534" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_a70d723f-0957-41d1-8c70-01ff19fb8e3e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_16d03381-9e4e-4cc7-89e3-c3ccb08e1f0b" xlink:to="loc_srt_StatementGeographicalAxis_a70d723f-0957-41d1-8c70-01ff19fb8e3e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_a70d723f-0957-41d1-8c70-01ff19fb8e3e_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_a70d723f-0957-41d1-8c70-01ff19fb8e3e" xlink:to="loc_srt_SegmentGeographicalDomain_a70d723f-0957-41d1-8c70-01ff19fb8e3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_568414a4-709e-4ab8-837e-341cddddca9a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_a70d723f-0957-41d1-8c70-01ff19fb8e3e" xlink:to="loc_srt_SegmentGeographicalDomain_568414a4-709e-4ab8-837e-341cddddca9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_3f4e1197-49ad-4c38-a8f4-8e4b7e4631a8" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_568414a4-709e-4ab8-837e-341cddddca9a" xlink:to="loc_srt_AmericasMember_3f4e1197-49ad-4c38-a8f4-8e4b7e4631a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_c23c8fe4-8fbe-4025-be79-61b90f1c9dba" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_568414a4-709e-4ab8-837e-341cddddca9a" xlink:to="loc_us-gaap_EMEAMember_c23c8fe4-8fbe-4025-be79-61b90f1c9dba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_8b7d3848-3e69-4a14-8efd-3e3df413ca8a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_568414a4-709e-4ab8-837e-341cddddca9a" xlink:to="loc_srt_AsiaPacificMember_8b7d3848-3e69-4a14-8efd-3e3df413ca8a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_250e2698-e13b-48b9-ac2b-5da8d8bd235a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_250e2698-e13b-48b9-ac2b-5da8d8bd235a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_OperatingIncomeLossSegmentReporting_1ca101f7-7541-446b-9c17-9175793c7c0e" xlink:href="kwr-20240930.xsd#kwr_OperatingIncomeLossSegmentReporting"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_kwr_OperatingIncomeLossSegmentReporting_1ca101f7-7541-446b-9c17-9175793c7c0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_0464efea-46f1-4709-a117-ceb6d93e6e31" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_RestructuringCharges_0464efea-46f1-4709-a117-ceb6d93e6e31" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_NonoperatingCharges_ec295c3c-9448-45f5-8558-f1e6645f33b5" xlink:href="kwr-20240930.xsd#kwr_NonoperatingCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_kwr_NonoperatingCharges_ec295c3c-9448-45f5-8558-f1e6645f33b5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDepreciationAndAmortization_7e8273eb-b855-4b82-8abb-f87e009d9810" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_OtherDepreciationAndAmortization_7e8273eb-b855-4b82-8abb-f87e009d9810" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_59536623-96fd-4364-bcf6-a5627350d831" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_OperatingIncomeLoss_59536623-96fd-4364-bcf6-a5627350d831" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_9452d8d7-e106-473e-b8e0-94e7a7f5ceaa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_9452d8d7-e106-473e-b8e0-94e7a7f5ceaa" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_d12b9f73-fc72-4de4-ad6d-010002ba58af" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_d12b9f73-fc72-4de4-ad6d-010002ba58af" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_89c65cda-5125-49fa-abaf-dbee79b64b22" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_af109625-9357-4bff-b193-6e09597274c8" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_89c65cda-5125-49fa-abaf-dbee79b64b22" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/NetSalesandRevenueRecognitionNarrativeDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#NetSalesandRevenueRecognitionNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/NetSalesandRevenueRecognitionNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_4ecc91d0-740e-45ef-a3a6-6dbd439edf66" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_325c2203-6aac-4d4a-a07c-914dedf7ece2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_4ecc91d0-740e-45ef-a3a6-6dbd439edf66" xlink:to="loc_us-gaap_ConcentrationRiskTable_325c2203-6aac-4d4a-a07c-914dedf7ece2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_1639d8d4-63fb-4a0d-983a-896b0d4315b0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_325c2203-6aac-4d4a-a07c-914dedf7ece2" xlink:to="loc_srt_MajorCustomersAxis_1639d8d4-63fb-4a0d-983a-896b0d4315b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_1639d8d4-63fb-4a0d-983a-896b0d4315b0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_1639d8d4-63fb-4a0d-983a-896b0d4315b0" xlink:to="loc_srt_NameOfMajorCustomerDomain_1639d8d4-63fb-4a0d-983a-896b0d4315b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_34f8436d-f603-489e-8955-d4305b0c0a98" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_1639d8d4-63fb-4a0d-983a-896b0d4315b0" xlink:to="loc_srt_NameOfMajorCustomerDomain_34f8436d-f603-489e-8955-d4305b0c0a98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_TopFiveMember_0679f784-5d8b-4e17-abe9-80c5b0c16224" xlink:href="kwr-20240930.xsd#kwr_TopFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_34f8436d-f603-489e-8955-d4305b0c0a98" xlink:to="loc_kwr_TopFiveMember_0679f784-5d8b-4e17-abe9-80c5b0c16224" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_LargestCustomerMember_a8d284ce-df61-4f7a-810e-9b2d1992b57f" xlink:href="kwr-20240930.xsd#kwr_LargestCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_34f8436d-f603-489e-8955-d4305b0c0a98" xlink:to="loc_kwr_LargestCustomerMember_a8d284ce-df61-4f7a-810e-9b2d1992b57f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ece3d645-7676-45d0-9f32-5cfa34e5d52a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_325c2203-6aac-4d4a-a07c-914dedf7ece2" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ece3d645-7676-45d0-9f32-5cfa34e5d52a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ece3d645-7676-45d0-9f32-5cfa34e5d52a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ece3d645-7676-45d0-9f32-5cfa34e5d52a" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ece3d645-7676-45d0-9f32-5cfa34e5d52a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_192bd5e6-8a2c-439a-95dc-05c42c5a5174" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ece3d645-7676-45d0-9f32-5cfa34e5d52a" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_192bd5e6-8a2c-439a-95dc-05c42c5a5174" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_1e096926-9364-4f23-89a1-1106b3d8b82f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_192bd5e6-8a2c-439a-95dc-05c42c5a5174" xlink:to="loc_us-gaap_SalesRevenueNetMember_1e096926-9364-4f23-89a1-1106b3d8b82f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_22c28fee-1028-458d-8dfe-cd982755ea68" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_325c2203-6aac-4d4a-a07c-914dedf7ece2" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_22c28fee-1028-458d-8dfe-cd982755ea68" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_22c28fee-1028-458d-8dfe-cd982755ea68_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_22c28fee-1028-458d-8dfe-cd982755ea68" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_22c28fee-1028-458d-8dfe-cd982755ea68_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_cde1b1bc-d0b1-4246-af79-5ea6bf8fe852" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_22c28fee-1028-458d-8dfe-cd982755ea68" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_cde1b1bc-d0b1-4246-af79-5ea6bf8fe852" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_008cc0c4-47de-4e02-9a64-79ac162f925a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_cde1b1bc-d0b1-4246-af79-5ea6bf8fe852" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_008cc0c4-47de-4e02-9a64-79ac162f925a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_Netreportingamount_ee31c103-4266-4532-af85-f5147bb751c4" xlink:href="kwr-20240930.xsd#kwr_Netreportingamount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_4ecc91d0-740e-45ef-a3a6-6dbd439edf66" xlink:to="loc_kwr_Netreportingamount_ee31c103-4266-4532-af85-f5147bb751c4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_d50cd079-8148-4ba9-b8a6-6d904cd53e79" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_4ecc91d0-740e-45ef-a3a6-6dbd439edf66" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_d50cd079-8148-4ba9-b8a6-6d904cd53e79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenue_12194c9d-3eb7-4169-9e0d-c755637b9c12" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_4ecc91d0-740e-45ef-a3a6-6dbd439edf66" xlink:to="loc_us-gaap_DeferredRevenue_12194c9d-3eb7-4169-9e0d-c755637b9c12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_8d73b6a5-671e-4326-b434-caac822a9662" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_4ecc91d0-740e-45ef-a3a6-6dbd439edf66" xlink:to="loc_us-gaap_NumberOfReportableSegments_8d73b6a5-671e-4326-b434-caac822a9662" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/NetSalesandRevenueRecognitionDisaggregatedRevenueDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#NetSalesandRevenueRecognitionDisaggregatedRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/NetSalesandRevenueRecognitionDisaggregatedRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductInformationLineItems_330603b0-6c6b-4eab-9253-87f3e296f68d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProductInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfProductInformationTable_a533a710-a681-4774-be27-eb67888532dd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfProductInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ProductInformationLineItems_330603b0-6c6b-4eab-9253-87f3e296f68d" xlink:to="loc_us-gaap_ScheduleOfProductInformationTable_a533a710-a681-4774-be27-eb67888532dd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_ec7be3ea-d076-4113-8c5e-6738dda4780c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfProductInformationTable_a533a710-a681-4774-be27-eb67888532dd" xlink:to="loc_srt_ConsolidationItemsAxis_ec7be3ea-d076-4113-8c5e-6738dda4780c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_ec7be3ea-d076-4113-8c5e-6738dda4780c_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_ec7be3ea-d076-4113-8c5e-6738dda4780c" xlink:to="loc_srt_ConsolidationItemsDomain_ec7be3ea-d076-4113-8c5e-6738dda4780c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_4e8b6c8d-8854-41b0-9043-a7908832258d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_ec7be3ea-d076-4113-8c5e-6738dda4780c" xlink:to="loc_srt_ConsolidationItemsDomain_4e8b6c8d-8854-41b0-9043-a7908832258d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_0e082d03-4048-4356-a1db-c9f504b3977f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_4e8b6c8d-8854-41b0-9043-a7908832258d" xlink:to="loc_us-gaap_OperatingSegmentsMember_0e082d03-4048-4356-a1db-c9f504b3977f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_664f3c8c-c2b8-4877-9bec-64de99f8e915" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfProductInformationTable_a533a710-a681-4774-be27-eb67888532dd" xlink:to="loc_srt_ProductOrServiceAxis_664f3c8c-c2b8-4877-9bec-64de99f8e915" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_664f3c8c-c2b8-4877-9bec-64de99f8e915_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_664f3c8c-c2b8-4877-9bec-64de99f8e915" xlink:to="loc_srt_ProductsAndServicesDomain_664f3c8c-c2b8-4877-9bec-64de99f8e915_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_2a137c76-34e8-4892-a5f8-2b28457900e7" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_664f3c8c-c2b8-4877-9bec-64de99f8e915" xlink:to="loc_srt_ProductsAndServicesDomain_2a137c76-34e8-4892-a5f8-2b28457900e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_MetalsMember_763f05f2-7276-4e94-8433-e8190d3e0096" xlink:href="kwr-20240930.xsd#kwr_MetalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_2a137c76-34e8-4892-a5f8-2b28457900e7" xlink:to="loc_kwr_MetalsMember_763f05f2-7276-4e94-8433-e8190d3e0096" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_MetalworkingAndOtherMember_88214057-29d2-476c-a870-487eba9c0329" xlink:href="kwr-20240930.xsd#kwr_MetalworkingAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_2a137c76-34e8-4892-a5f8-2b28457900e7" xlink:to="loc_kwr_MetalworkingAndOtherMember_88214057-29d2-476c-a870-487eba9c0329" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_fa16f6ac-cfe4-4510-8e1e-9b2dfbb1f702" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfProductInformationTable_a533a710-a681-4774-be27-eb67888532dd" xlink:to="loc_srt_StatementGeographicalAxis_fa16f6ac-cfe4-4510-8e1e-9b2dfbb1f702" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_fa16f6ac-cfe4-4510-8e1e-9b2dfbb1f702_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_fa16f6ac-cfe4-4510-8e1e-9b2dfbb1f702" xlink:to="loc_srt_SegmentGeographicalDomain_fa16f6ac-cfe4-4510-8e1e-9b2dfbb1f702_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_21a2b13e-1c02-4a4c-9891-55e1b84dc5f1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_fa16f6ac-cfe4-4510-8e1e-9b2dfbb1f702" xlink:to="loc_srt_SegmentGeographicalDomain_21a2b13e-1c02-4a4c-9891-55e1b84dc5f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_3b3386ec-c236-463a-b3f0-b82a1568557d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_21a2b13e-1c02-4a4c-9891-55e1b84dc5f1" xlink:to="loc_srt_AmericasMember_3b3386ec-c236-463a-b3f0-b82a1568557d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_08b0e3be-030f-466e-a995-919d7ea5e3fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_21a2b13e-1c02-4a4c-9891-55e1b84dc5f1" xlink:to="loc_us-gaap_EMEAMember_08b0e3be-030f-466e-a995-919d7ea5e3fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_c0930df2-ff8e-4501-9a5e-13408f881a74" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_21a2b13e-1c02-4a4c-9891-55e1b84dc5f1" xlink:to="loc_srt_AsiaPacificMember_c0930df2-ff8e-4501-9a5e-13408f881a74" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f68428d3-588b-4aaa-bd90-54ccc053ef0d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductInformationLineItems_330603b0-6c6b-4eab-9253-87f3e296f68d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f68428d3-588b-4aaa-bd90-54ccc053ef0d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#LeasesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/LeasesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_db73490c-7532-4c53-b792-da24ca416cf2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_ab08e3cc-9293-42f3-bc0c-4e65220008b5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_db73490c-7532-4c53-b792-da24ca416cf2" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_ab08e3cc-9293-42f3-bc0c-4e65220008b5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fcdda30f-ec91-4f1e-bd12-675fe3f3b0fe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_ab08e3cc-9293-42f3-bc0c-4e65220008b5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fcdda30f-ec91-4f1e-bd12-675fe3f3b0fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fcdda30f-ec91-4f1e-bd12-675fe3f3b0fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fcdda30f-ec91-4f1e-bd12-675fe3f3b0fe" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fcdda30f-ec91-4f1e-bd12-675fe3f3b0fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fceea00f-5e03-4843-86f6-71d5990b3ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fcdda30f-ec91-4f1e-bd12-675fe3f3b0fe" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fceea00f-5e03-4843-86f6-71d5990b3ec1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_FacilitiesVehiclesAndMachineryAndEquipmentMember_198c6dc8-f8f4-46b4-988d-27f9a249415d" xlink:href="kwr-20240930.xsd#kwr_FacilitiesVehiclesAndMachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fceea00f-5e03-4843-86f6-71d5990b3ec1" xlink:to="loc_kwr_FacilitiesVehiclesAndMachineryAndEquipmentMember_198c6dc8-f8f4-46b4-988d-27f9a249415d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_6af66ed0-b2f3-4260-90fa-9392a5eaf69e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fceea00f-5e03-4843-86f6-71d5990b3ec1" xlink:to="loc_us-gaap_LandMember_6af66ed0-b2f3-4260-90fa-9392a5eaf69e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_29b699f3-2c20-4f9a-bea8-f92b611b047c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_db73490c-7532-4c53-b792-da24ca416cf2" xlink:to="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_29b699f3-2c20-4f9a-bea8-f92b611b047c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableLeaseCost_3a1f49fc-6910-4611-b455-c9d576d94c58" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_db73490c-7532-4c53-b792-da24ca416cf2" xlink:to="loc_us-gaap_VariableLeaseCost_3a1f49fc-6910-4611-b455-c9d576d94c58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubleaseIncome_9edfbe63-fbb1-4994-9df0-d28916fad4a3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubleaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_db73490c-7532-4c53-b792-da24ca416cf2" xlink:to="loc_us-gaap_SubleaseIncome_9edfbe63-fbb1-4994-9df0-d28916fad4a3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/RestructuringandRelatedActivitiesDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#RestructuringandRelatedActivitiesDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/RestructuringandRelatedActivitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_023408de-84c0-4f68-93ab-91c81dd3d8fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_a598a277-29e5-4a09-838c-3ec10884a5b7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_023408de-84c0-4f68-93ab-91c81dd3d8fa" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_a598a277-29e5-4a09-838c-3ec10884a5b7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanAxis_fe36bf3d-16ea-4ee9-9594-636108532503" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringPlanAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_a598a277-29e5-4a09-838c-3ec10884a5b7" xlink:to="loc_us-gaap_RestructuringPlanAxis_fe36bf3d-16ea-4ee9-9594-636108532503" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_fe36bf3d-16ea-4ee9-9594-636108532503_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringPlanAxis_fe36bf3d-16ea-4ee9-9594-636108532503" xlink:to="loc_us-gaap_RestructuringPlanDomain_fe36bf3d-16ea-4ee9-9594-636108532503_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_bdd2c3d6-d535-4786-9bd8-3bc3da29bd31" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringPlanAxis_fe36bf3d-16ea-4ee9-9594-636108532503" xlink:to="loc_us-gaap_RestructuringPlanDomain_bdd2c3d6-d535-4786-9bd8-3bc3da29bd31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringChargesMember_cbbc2fb9-af29-4a73-9afc-a4bcff10293c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringChargesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_bdd2c3d6-d535-4786-9bd8-3bc3da29bd31" xlink:to="loc_us-gaap_RestructuringChargesMember_cbbc2fb9-af29-4a73-9afc-a4bcff10293c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated_6e0d3268-415c-4b8c-b18b-2ce087549507" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_023408de-84c0-4f68-93ab-91c81dd3d8fa" xlink:to="loc_us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated_6e0d3268-415c-4b8c-b18b-2ce087549507" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateHeldforsale_8d6e98f3-74a3-4045-83c2-69a08f6eba64" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateHeldforsale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_023408de-84c0-4f68-93ab-91c81dd3d8fa" xlink:to="loc_us-gaap_RealEstateHeldforsale_8d6e98f3-74a3-4045-83c2-69a08f6eba64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveRollForward_869feaa8-a347-4253-821e-51868c62c9fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserveRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_023408de-84c0-4f68-93ab-91c81dd3d8fa" xlink:to="loc_us-gaap_RestructuringReserveRollForward_869feaa8-a347-4253-821e-51868c62c9fa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_c4ab554a-1ff1-40b2-9721-21b001e43a3c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_869feaa8-a347-4253-821e-51868c62c9fa" xlink:to="loc_us-gaap_RestructuringReserve_c4ab554a-1ff1-40b2-9721-21b001e43a3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_3fe99733-3008-4daa-bf10-89ed2a9eec52" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_869feaa8-a347-4253-821e-51868c62c9fa" xlink:to="loc_us-gaap_RestructuringCharges_3fe99733-3008-4daa-bf10-89ed2a9eec52" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRestructuring_ae59b098-847b-4e2d-b160-7b7759ee721d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsForRestructuring"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_869feaa8-a347-4253-821e-51868c62c9fa" xlink:to="loc_us-gaap_PaymentsForRestructuring_ae59b098-847b-4e2d-b160-7b7759ee721d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveTranslationAdjustment_b35a33b8-d786-42a2-b099-6c83b5333ecd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserveTranslationAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_869feaa8-a347-4253-821e-51868c62c9fa" xlink:to="loc_us-gaap_RestructuringReserveTranslationAdjustment_b35a33b8-d786-42a2-b099-6c83b5333ecd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_75fff821-abfe-45b8-a1bb-3bc2ca524ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserve"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherAssets_3f668841-2a11-4db4-b13b-a6e79e0208b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainLossOnSaleOfOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_023408de-84c0-4f68-93ab-91c81dd3d8fa" xlink:to="loc_us-gaap_GainLossOnSaleOfOtherAssets_3f668841-2a11-4db4-b13b-a6e79e0208b2" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/ShareBasedCompensationSharebasedCompensationExpenseDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#ShareBasedCompensationSharebasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/ShareBasedCompensationSharebasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_713a6c01-127a-431e-9e3b-71c2cfe8d24d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_cebfb2f9-5d7e-4da9-a4df-c9d55cb0741e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_713a6c01-127a-431e-9e3b-71c2cfe8d24d" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_cebfb2f9-5d7e-4da9-a4df-c9d55cb0741e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_b8ce7e06-104c-407c-9c74-6c2be77e8ffa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_cebfb2f9-5d7e-4da9-a4df-c9d55cb0741e" xlink:to="loc_us-gaap_AwardTypeAxis_b8ce7e06-104c-407c-9c74-6c2be77e8ffa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b8ce7e06-104c-407c-9c74-6c2be77e8ffa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_b8ce7e06-104c-407c-9c74-6c2be77e8ffa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b8ce7e06-104c-407c-9c74-6c2be77e8ffa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1808943-1301-4ebe-988d-c921b32dcddf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_b8ce7e06-104c-407c-9c74-6c2be77e8ffa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1808943-1301-4ebe-988d-c921b32dcddf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_StockOptionsCompensationExpenseMember_08f536d5-7efe-4b16-ad5b-9f9866b5d81d" xlink:href="kwr-20240930.xsd#kwr_StockOptionsCompensationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1808943-1301-4ebe-988d-c921b32dcddf" xlink:to="loc_kwr_StockOptionsCompensationExpenseMember_08f536d5-7efe-4b16-ad5b-9f9866b5d81d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_NonvestedStockAwardsCompensationExpenseMember_9fbab613-2d9b-4188-88c9-44c414c1b874" xlink:href="kwr-20240930.xsd#kwr_NonvestedStockAwardsCompensationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1808943-1301-4ebe-988d-c921b32dcddf" xlink:to="loc_kwr_NonvestedStockAwardsCompensationExpenseMember_9fbab613-2d9b-4188-88c9-44c414c1b874" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_DirectorsStockOwnershipPlanCompensationExpenseMember_b3dece11-4571-44a5-8794-1f56731ca2a5" xlink:href="kwr-20240930.xsd#kwr_DirectorsStockOwnershipPlanCompensationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1808943-1301-4ebe-988d-c921b32dcddf" xlink:to="loc_kwr_DirectorsStockOwnershipPlanCompensationExpenseMember_b3dece11-4571-44a5-8794-1f56731ca2a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_5c903ed4-c291-44f9-b492-73329e41286c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b1808943-1301-4ebe-988d-c921b32dcddf" xlink:to="loc_us-gaap_PerformanceSharesMember_5c903ed4-c291-44f9-b492-73329e41286c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_f5982671-977e-4082-8e77-48097b69d964" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_713a6c01-127a-431e-9e3b-71c2cfe8d24d" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_f5982671-977e-4082-8e77-48097b69d964" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/ShareBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#ShareBasedCompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/ShareBasedCompensationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_da341499-567c-4606-8b56-2695fb056962" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_da341499-567c-4606-8b56-2695fb056962" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_76a7744c-9eae-45f4-9cd2-406cc508c174" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_da341499-567c-4606-8b56-2695fb056962" xlink:to="loc_us-gaap_AwardTypeAxis_76a7744c-9eae-45f4-9cd2-406cc508c174" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76a7744c-9eae-45f4-9cd2-406cc508c174_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_76a7744c-9eae-45f4-9cd2-406cc508c174" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76a7744c-9eae-45f4-9cd2-406cc508c174_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_76a7744c-9eae-45f4-9cd2-406cc508c174" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_23bf328a-7023-4582-8de5-20c562e6b9a9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:to="loc_us-gaap_EmployeeStockOptionMember_23bf328a-7023-4582-8de5-20c562e6b9a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_cc11bb5f-766b-4236-be8f-bcb416711317" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:to="loc_us-gaap_RestrictedStockMember_cc11bb5f-766b-4236-be8f-bcb416711317" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_71a4032d-fa7f-48da-992e-13a03fc5229f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_71a4032d-fa7f-48da-992e-13a03fc5229f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_181827ac-3860-4ab6-88ac-a6298262004b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:to="loc_us-gaap_PerformanceSharesMember_181827ac-3860-4ab6-88ac-a6298262004b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_PerformanceStockUnitsROICMember_11e82b2c-673d-4e12-87fa-c206efaaab31" xlink:href="kwr-20240930.xsd#kwr_PerformanceStockUnitsROICMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:to="loc_kwr_PerformanceStockUnitsROICMember_11e82b2c-673d-4e12-87fa-c206efaaab31" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_PerformanceStockUnitsTSRMember_5912902a-e8a0-4ca1-8b2f-5ccbfe54f46d" xlink:href="kwr-20240930.xsd#kwr_PerformanceStockUnitsTSRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6c59d3da-bb34-43d9-9a8e-e43f953ef6cb" xlink:to="loc_kwr_PerformanceStockUnitsTSRMember_5912902a-e8a0-4ca1-8b2f-5ccbfe54f46d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_cf84edd7-ec94-4052-8121-50125d298539" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_da341499-567c-4606-8b56-2695fb056962" xlink:to="loc_srt_RangeAxis_cf84edd7-ec94-4052-8121-50125d298539" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_cf84edd7-ec94-4052-8121-50125d298539_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_cf84edd7-ec94-4052-8121-50125d298539" xlink:to="loc_srt_RangeMember_cf84edd7-ec94-4052-8121-50125d298539_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2c5b8799-c123-4026-9601-881c57aedeed" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_cf84edd7-ec94-4052-8121-50125d298539" xlink:to="loc_srt_RangeMember_2c5b8799-c123-4026-9601-881c57aedeed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_3d341f41-82e4-46d0-b4cb-d9e1e2d4a11f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2c5b8799-c123-4026-9601-881c57aedeed" xlink:to="loc_srt_MinimumMember_3d341f41-82e4-46d0-b4cb-d9e1e2d4a11f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3bdd7af0-5361-4edd-86ae-86a5ef1d98c6" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2c5b8799-c123-4026-9601-881c57aedeed" xlink:to="loc_srt_MaximumMember_3bdd7af0-5361-4edd-86ae-86a5ef1d98c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_9ca1ea73-b00b-49b7-b662-b795fcb50e46" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_9ca1ea73-b00b-49b7-b662-b795fcb50e46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_1a8d36a8-0d95-471a-bfe6-7c6b3b72da69" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_1a8d36a8-0d95-471a-bfe6-7c6b3b72da69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_ee747fb9-0ce0-4245-9ed6-88a3fe20b3aa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_ee747fb9-0ce0-4245-9ed6-88a3fe20b3aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3be56786-e29c-48ee-b514-a7ebcf248ebc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3be56786-e29c-48ee-b514-a7ebcf248ebc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_ef1bde7f-34e9-4c89-8fce-e7fe0c5cff7b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_ef1bde7f-34e9-4c89-8fce-e7fe0c5cff7b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_e0b841d9-73b1-4666-89ee-dbe61919befe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_e0b841d9-73b1-4666-89ee-dbe61919befe" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_Vestingsharestargetlowerpercent_c6b9feed-8fe3-44af-8309-722e70718e30" xlink:href="kwr-20240930.xsd#kwr_Vestingsharestargetlowerpercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_kwr_Vestingsharestargetlowerpercent_c6b9feed-8fe3-44af-8309-722e70718e30" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_Vestingsharestargetupperpercent_e629c9e3-6da3-42db-bd49-3570f80f6641" xlink:href="kwr-20240930.xsd#kwr_Vestingsharestargetupperpercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_kwr_Vestingsharestargetupperpercent_e629c9e3-6da3-42db-bd49-3570f80f6641" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4ec1d443-c188-4363-b19f-0c7287c01f61" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_0882b35b-7dd9-4243-913a-a94c45ae58be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4ec1d443-c188-4363-b19f-0c7287c01f61" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/ShareBasedCompensationMonteCarloSimulationonGrantDateDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#ShareBasedCompensationMonteCarloSimulationonGrantDateDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/ShareBasedCompensationMonteCarloSimulationonGrantDateDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_42775a2a-4ea1-4a7d-8f15-dbe9e8a842c6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_ab6e9936-9cfe-42b9-83a3-6be0299f05ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_42775a2a-4ea1-4a7d-8f15-dbe9e8a842c6" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_ab6e9936-9cfe-42b9-83a3-6be0299f05ab" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_701dcd09-5a42-448f-81fb-8dd896071d32" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_ab6e9936-9cfe-42b9-83a3-6be0299f05ab" xlink:to="loc_us-gaap_AwardTypeAxis_701dcd09-5a42-448f-81fb-8dd896071d32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_701dcd09-5a42-448f-81fb-8dd896071d32_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_701dcd09-5a42-448f-81fb-8dd896071d32" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_701dcd09-5a42-448f-81fb-8dd896071d32_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09d11259-53e1-4bc8-a0c8-9ccd08521d1d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_701dcd09-5a42-448f-81fb-8dd896071d32" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09d11259-53e1-4bc8-a0c8-9ccd08521d1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_d861b00b-a21e-4a93-bc07-11a250ef303a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09d11259-53e1-4bc8-a0c8-9ccd08521d1d" xlink:to="loc_us-gaap_PerformanceSharesMember_d861b00b-a21e-4a93-bc07-11a250ef303a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_c0482d75-4fea-409e-b06c-64c4ab171e1f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_42775a2a-4ea1-4a7d-8f15-dbe9e8a842c6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_c0482d75-4fea-409e-b06c-64c4ab171e1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_3c878585-14c6-4512-a002-06c9159ea355" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_42775a2a-4ea1-4a7d-8f15-dbe9e8a842c6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_3c878585-14c6-4512-a002-06c9159ea355" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_d89025f0-00f9-4927-a369-a0194da14ba7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_3c878585-14c6-4512-a002-06c9159ea355" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_d89025f0-00f9-4927-a369-a0194da14ba7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_41f60591-b425-48b5-a455-a2990a830acd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_3c878585-14c6-4512-a002-06c9159ea355" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_41f60591-b425-48b5-a455-a2990a830acd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_8292a5dc-2d89-4b12-9fc9-f4a13e553a78" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_3c878585-14c6-4512-a002-06c9159ea355" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_8292a5dc-2d89-4b12-9fc9-f4a13e553a78" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/PensionandOtherPostretirementBenefitsNetPeriodicBenefitCostDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#PensionandOtherPostretirementBenefitsNetPeriodicBenefitCostDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/PensionandOtherPostretirementBenefitsNetPeriodicBenefitCostDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_7fd1bc0a-0f3a-472a-8496-70096eceab2d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f715b087-e576-43b5-bb49-9d7797786754" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_7fd1bc0a-0f3a-472a-8496-70096eceab2d" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f715b087-e576-43b5-bb49-9d7797786754" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_cad013a7-773c-4447-9fb0-aa657d1c72e8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f715b087-e576-43b5-bb49-9d7797786754" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_cad013a7-773c-4447-9fb0-aa657d1c72e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_cad013a7-773c-4447-9fb0-aa657d1c72e8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_cad013a7-773c-4447-9fb0-aa657d1c72e8" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_cad013a7-773c-4447-9fb0-aa657d1c72e8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_eca9df33-0293-48b8-a7cb-ac78b6bebfee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_cad013a7-773c-4447-9fb0-aa657d1c72e8" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_eca9df33-0293-48b8-a7cb-ac78b6bebfee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_d9515938-f499-4887-b40b-d63c06ea1da8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_eca9df33-0293-48b8-a7cb-ac78b6bebfee" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_d9515938-f499-4887-b40b-d63c06ea1da8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_18dc1630-3adb-4a2b-bdb1-1432c3996429" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_eca9df33-0293-48b8-a7cb-ac78b6bebfee" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_18dc1630-3adb-4a2b-bdb1-1432c3996429" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_7fd1bc0a-0f3a-472a-8496-70096eceab2d" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_DefinedBenefitPlanServiceCostNet_a4324f86-c3ee-4f8c-bc3d-ff02d1834604" xlink:href="kwr-20240930.xsd#kwr_DefinedBenefitPlanServiceCostNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:to="loc_kwr_DefinedBenefitPlanServiceCostNet_a4324f86-c3ee-4f8c-bc3d-ff02d1834604" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_2dd884f6-fe05-4f13-9035-04149f2ae40e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_2dd884f6-fe05-4f13-9035-04149f2ae40e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_974e190b-14f9-4239-940b-1d7f4abbfd4a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_974e190b-14f9-4239-940b-1d7f4abbfd4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_6d67c773-8150-4b5a-9235-880b94bcb7f4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_6d67c773-8150-4b5a-9235-880b94bcb7f4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_ffeb1bbd-31f7-4259-9c09-0062402a8e42" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_ffeb1bbd-31f7-4259-9c09-0062402a8e42" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_fe5cb15d-cb8a-4426-b131-bac0a81158df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_594dbc01-1329-4fb3-8b3b-28a66472618c" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_fe5cb15d-cb8a-4426-b131-bac0a81158df" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/PensionandOtherPostretirementBenefitsNarrativeDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#PensionandOtherPostretirementBenefitsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/PensionandOtherPostretirementBenefitsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_b999c515-473c-408d-b607-88231afa9972" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_124ae4ef-b95f-4e06-a1e8-50372c732b99" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_b999c515-473c-408d-b607-88231afa9972" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_124ae4ef-b95f-4e06-a1e8-50372c732b99" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_80c6822d-0d80-4529-8e4f-4c348a0dd495" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_124ae4ef-b95f-4e06-a1e8-50372c732b99" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_80c6822d-0d80-4529-8e4f-4c348a0dd495" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_80c6822d-0d80-4529-8e4f-4c348a0dd495_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_80c6822d-0d80-4529-8e4f-4c348a0dd495" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_80c6822d-0d80-4529-8e4f-4c348a0dd495_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_a7c591d8-44d6-442e-811f-55391e815cd8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_80c6822d-0d80-4529-8e4f-4c348a0dd495" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_a7c591d8-44d6-442e-811f-55391e815cd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_330826a8-8e04-4310-a98f-4cff68546d63" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_a7c591d8-44d6-442e-811f-55391e815cd8" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_330826a8-8e04-4310-a98f-4cff68546d63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_685386e1-d7ef-45d7-a1b9-f6d3f5ecdaec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_a7c591d8-44d6-442e-811f-55391e815cd8" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_685386e1-d7ef-45d7-a1b9-f6d3f5ecdaec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_d4c878a6-f03c-4f2b-9745-389ffeb541a6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_b999c515-473c-408d-b607-88231afa9972" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_d4c878a6-f03c-4f2b-9745-389ffeb541a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_db226acc-600a-4151-bb66-9495be7a7b6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_b999c515-473c-408d-b607-88231afa9972" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_db226acc-600a-4151-bb66-9495be7a7b6c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/GoodwillandOtherIntangibleAssetsChangesinCarryingAmountofGoodwillDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#GoodwillandOtherIntangibleAssetsChangesinCarryingAmountofGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/GoodwillandOtherIntangibleAssetsChangesinCarryingAmountofGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_363f29d9-0971-42e8-95e5-7e30f0735b7d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_aa74c9f5-f6f4-46c7-8c1a-39f08fc1f12d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_363f29d9-0971-42e8-95e5-7e30f0735b7d" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_aa74c9f5-f6f4-46c7-8c1a-39f08fc1f12d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_569b8b2b-4b91-4455-a8d6-2432b28f0df0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_aa74c9f5-f6f4-46c7-8c1a-39f08fc1f12d" xlink:to="loc_srt_ConsolidationItemsAxis_569b8b2b-4b91-4455-a8d6-2432b28f0df0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_569b8b2b-4b91-4455-a8d6-2432b28f0df0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_569b8b2b-4b91-4455-a8d6-2432b28f0df0" xlink:to="loc_srt_ConsolidationItemsDomain_569b8b2b-4b91-4455-a8d6-2432b28f0df0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_c40824b9-4969-4b8d-beea-004e97d6f96c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_569b8b2b-4b91-4455-a8d6-2432b28f0df0" xlink:to="loc_srt_ConsolidationItemsDomain_c40824b9-4969-4b8d-beea-004e97d6f96c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_86389685-8e96-48b5-84e5-82a33ba68113" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_c40824b9-4969-4b8d-beea-004e97d6f96c" xlink:to="loc_us-gaap_OperatingSegmentsMember_86389685-8e96-48b5-84e5-82a33ba68113" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementAxis_177cdb7e-1b6c-40ab-aa1a-23454e01066b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RestatementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_aa74c9f5-f6f4-46c7-8c1a-39f08fc1f12d" xlink:to="loc_srt_RestatementAxis_177cdb7e-1b6c-40ab-aa1a-23454e01066b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_177cdb7e-1b6c-40ab-aa1a-23454e01066b_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RestatementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RestatementAxis_177cdb7e-1b6c-40ab-aa1a-23454e01066b" xlink:to="loc_srt_RestatementDomain_177cdb7e-1b6c-40ab-aa1a-23454e01066b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_6387f36c-25e1-4414-87dc-d9b43def77aa" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RestatementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RestatementAxis_177cdb7e-1b6c-40ab-aa1a-23454e01066b" xlink:to="loc_srt_RestatementDomain_6387f36c-25e1-4414-87dc-d9b43def77aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioPreviouslyReportedMember_e8ef199c-f322-4a14-816c-f8494473a6b3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioPreviouslyReportedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RestatementDomain_6387f36c-25e1-4414-87dc-d9b43def77aa" xlink:to="loc_srt_ScenarioPreviouslyReportedMember_e8ef199c-f322-4a14-816c-f8494473a6b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_8fe1f212-5404-4715-8ca1-e007a5777e45" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_aa74c9f5-f6f4-46c7-8c1a-39f08fc1f12d" xlink:to="loc_srt_StatementGeographicalAxis_8fe1f212-5404-4715-8ca1-e007a5777e45" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_8fe1f212-5404-4715-8ca1-e007a5777e45_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_8fe1f212-5404-4715-8ca1-e007a5777e45" xlink:to="loc_srt_SegmentGeographicalDomain_8fe1f212-5404-4715-8ca1-e007a5777e45_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_f5de656f-09ab-446a-b44f-790c4acd1b03" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_8fe1f212-5404-4715-8ca1-e007a5777e45" xlink:to="loc_srt_SegmentGeographicalDomain_f5de656f-09ab-446a-b44f-790c4acd1b03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_c6746983-f7f9-43be-97c6-824bfc226c61" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_f5de656f-09ab-446a-b44f-790c4acd1b03" xlink:to="loc_srt_AmericasMember_c6746983-f7f9-43be-97c6-824bfc226c61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_bd955bed-219c-4b80-8fdd-cceef9189208" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_f5de656f-09ab-446a-b44f-790c4acd1b03" xlink:to="loc_us-gaap_EMEAMember_bd955bed-219c-4b80-8fdd-cceef9189208" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_68742975-78d8-4ad1-ab87-891babe80933" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_f5de656f-09ab-446a-b44f-790c4acd1b03" xlink:to="loc_srt_AsiaPacificMember_68742975-78d8-4ad1-ab87-891babe80933" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_fc02410c-8ca5-453c-996f-2f6be49fbdf6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_363f29d9-0971-42e8-95e5-7e30f0735b7d" xlink:to="loc_us-gaap_GoodwillRollForward_fc02410c-8ca5-453c-996f-2f6be49fbdf6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_fe48ad35-e59e-4cad-9eb0-cbfdc0ea4e7c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_fc02410c-8ca5-453c-996f-2f6be49fbdf6" xlink:to="loc_us-gaap_Goodwill_fe48ad35-e59e-4cad-9eb0-cbfdc0ea4e7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_0a644159-7493-4c67-83fd-7bf7e8d01111" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_fc02410c-8ca5-453c-996f-2f6be49fbdf6" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_0a644159-7493-4c67-83fd-7bf7e8d01111" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_bbf14ac1-a420-4c16-bf1a-b69d8dc0f63b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_fc02410c-8ca5-453c-996f-2f6be49fbdf6" xlink:to="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_bbf14ac1-a420-4c16-bf1a-b69d8dc0f63b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_4b07cb80-c729-445f-8642-1c1f3bf8b109" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/GoodwillandOtherIntangibleAssetsGrossCarryingAmountsandAccumulatedAmortizationforDefinitelivedIntangibleAssetsDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#GoodwillandOtherIntangibleAssetsGrossCarryingAmountsandAccumulatedAmortizationforDefinitelivedIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/GoodwillandOtherIntangibleAssetsGrossCarryingAmountsandAccumulatedAmortizationforDefinitelivedIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1bded5ba-3bb5-4b6c-8365-65ce446c9df1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a842d0a7-c178-4b44-97cd-b34575b4f608" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1bded5ba-3bb5-4b6c-8365-65ce446c9df1" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a842d0a7-c178-4b44-97cd-b34575b4f608" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e62ab23d-b50b-4d75-b547-14fd65527358" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a842d0a7-c178-4b44-97cd-b34575b4f608" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e62ab23d-b50b-4d75-b547-14fd65527358" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e62ab23d-b50b-4d75-b547-14fd65527358_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e62ab23d-b50b-4d75-b547-14fd65527358" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e62ab23d-b50b-4d75-b547-14fd65527358_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ab88a056-491d-40b9-8fd4-7fa9da5b79b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e62ab23d-b50b-4d75-b547-14fd65527358" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ab88a056-491d-40b9-8fd4-7fa9da5b79b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerListsMember_e6a7b11b-fa2e-4f97-8223-20ffedfc299e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerListsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ab88a056-491d-40b9-8fd4-7fa9da5b79b0" xlink:to="loc_us-gaap_CustomerListsMember_e6a7b11b-fa2e-4f97-8223-20ffedfc299e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_TrademarksFormulationsandproducttechnologymemberMember_062edfa3-9224-4fe4-a872-83aa21d095d9" xlink:href="kwr-20240930.xsd#kwr_TrademarksFormulationsandproducttechnologymemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ab88a056-491d-40b9-8fd4-7fa9da5b79b0" xlink:to="loc_kwr_TrademarksFormulationsandproducttechnologymemberMember_062edfa3-9224-4fe4-a872-83aa21d095d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_34fa42b7-f2d9-47a0-b158-a25801fcbf58" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ab88a056-491d-40b9-8fd4-7fa9da5b79b0" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_34fa42b7-f2d9-47a0-b158-a25801fcbf58" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_8246db19-dceb-4b48-9aa9-bd4fe0d1e03c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1bded5ba-3bb5-4b6c-8365-65ce446c9df1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_8246db19-dceb-4b48-9aa9-bd4fe0d1e03c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_74849fdb-ddf8-4b47-a9a3-6e2d6e004ce7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1bded5ba-3bb5-4b6c-8365-65ce446c9df1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_74849fdb-ddf8-4b47-a9a3-6e2d6e004ce7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_136075d6-d7f2-4aef-a100-d121b858cb14" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1bded5ba-3bb5-4b6c-8365-65ce446c9df1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_136075d6-d7f2-4aef-a100-d121b858cb14" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/GoodwillandOtherIntangibleAssetsIndefiniteLivedDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#GoodwillandOtherIntangibleAssetsIndefiniteLivedDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/GoodwillandOtherIntangibleAssetsIndefiniteLivedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5f2e9227-819d-406e-bb85-6921501287cc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_d57d4531-205d-488b-b782-4037b8431c2c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5f2e9227-819d-406e-bb85-6921501287cc" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_d57d4531-205d-488b-b782-4037b8431c2c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_465c0e95-49e7-4296-9417-62399d8b9447" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_d57d4531-205d-488b-b782-4037b8431c2c" xlink:to="loc_srt_StatementGeographicalAxis_465c0e95-49e7-4296-9417-62399d8b9447" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_465c0e95-49e7-4296-9417-62399d8b9447_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_465c0e95-49e7-4296-9417-62399d8b9447" xlink:to="loc_srt_SegmentGeographicalDomain_465c0e95-49e7-4296-9417-62399d8b9447_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_ced265ec-3be0-4cde-8077-4b48691a3cd6" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_465c0e95-49e7-4296-9417-62399d8b9447" xlink:to="loc_srt_SegmentGeographicalDomain_ced265ec-3be0-4cde-8077-4b48691a3cd6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_HoughtonCombinationMember_a94dbef5-4de2-44ae-8b5d-9e2b79315943" xlink:href="kwr-20240930.xsd#kwr_HoughtonCombinationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_ced265ec-3be0-4cde-8077-4b48691a3cd6" xlink:to="loc_kwr_HoughtonCombinationMember_a94dbef5-4de2-44ae-8b5d-9e2b79315943" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_5ffdb15a-19bc-42f2-aa12-92f5ea775a0a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5f2e9227-819d-406e-bb85-6921501287cc" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_5ffdb15a-19bc-42f2-aa12-92f5ea775a0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedTrademarks_47427e9b-3f40-40b5-8f1d-589660e09951" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedTrademarks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5f2e9227-819d-406e-bb85-6921501287cc" xlink:to="loc_us-gaap_IndefiniteLivedTrademarks_47427e9b-3f40-40b5-8f1d-589660e09951" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/DebtScheduleofDebtDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#DebtScheduleofDebtDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/DebtScheduleofDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_a3325512-483f-4fdf-99dc-bb9ad1207971" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:to="loc_us-gaap_DebtInstrumentTable_a3325512-483f-4fdf-99dc-bb9ad1207971" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_c452b553-d74d-48b3-89cc-9a2a3bf7bbb9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a3325512-483f-4fdf-99dc-bb9ad1207971" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_c452b553-d74d-48b3-89cc-9a2a3bf7bbb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_c452b553-d74d-48b3-89cc-9a2a3bf7bbb9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c452b553-d74d-48b3-89cc-9a2a3bf7bbb9" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_c452b553-d74d-48b3-89cc-9a2a3bf7bbb9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c452b553-d74d-48b3-89cc-9a2a3bf7bbb9" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedRevolverMember_0efb994f-2b85-4923-beff-a8d29bad8211" xlink:href="kwr-20240930.xsd#kwr_AmendedRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:to="loc_kwr_AmendedRevolverMember_0efb994f-2b85-4923-beff-a8d29bad8211" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedUsTermLoanMember_70ec415e-9094-48f2-9422-221b39c58bcf" xlink:href="kwr-20240930.xsd#kwr_AmendedUsTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:to="loc_kwr_AmendedUsTermLoanMember_70ec415e-9094-48f2-9422-221b39c58bcf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedEuroTermLoanMember_07edcf93-9934-455e-a1e0-d330fa8df12e" xlink:href="kwr-20240930.xsd#kwr_AmendedEuroTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:to="loc_kwr_AmendedEuroTermLoanMember_07edcf93-9934-455e-a1e0-d330fa8df12e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_IndustrialDevelopmentBondsMember_2e5d66db-4d71-48a6-94ad-38f20e2e6fc1" xlink:href="kwr-20240930.xsd#kwr_IndustrialDevelopmentBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:to="loc_kwr_IndustrialDevelopmentBondsMember_2e5d66db-4d71-48a6-94ad-38f20e2e6fc1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_BankLinesOfCreditAndOtherDebtObligationsMember_698f7518-47a7-4109-98f9-98882c62fc6d" xlink:href="kwr-20240930.xsd#kwr_BankLinesOfCreditAndOtherDebtObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b00ca9af-5e9b-43ae-b7d4-c980ccd863cd" xlink:to="loc_kwr_BankLinesOfCreditAndOtherDebtObligationsMember_698f7518-47a7-4109-98f9-98882c62fc6d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_10171385-8d37-46f2-ab72-b2e28c6c6582" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_10171385-8d37-46f2-ab72-b2e28c6c6582" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_50df8427-da51-49b8-91bf-d2090c3430cd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_50df8427-da51-49b8-91bf-d2090c3430cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_420480a4-1c27-4f8d-80a2-3cc2df195280" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_420480a4-1c27-4f8d-80a2-3cc2df195280" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_92045c6a-be9d-4c5c-a0a8-0545048eb4a6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:to="loc_us-gaap_ShortTermBorrowings_92045c6a-be9d-4c5c-a0a8-0545048eb4a6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_d8af5b05-52cf-4b39-b331-a4cb8b4c4ca6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_e7bee81c-60a5-4ed2-9083-9991c88d42e3" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_d8af5b05-52cf-4b39-b331-a4cb8b4c4ca6" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#DebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/DebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_4f251448-9588-46c6-b282-d24be1fab551" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_4f251448-9588-46c6-b282-d24be1fab551" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4f251448-9588-46c6-b282-d24be1fab551_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4f251448-9588-46c6-b282-d24be1fab551" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4f251448-9588-46c6-b282-d24be1fab551_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4f251448-9588-46c6-b282-d24be1fab551" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedEuroTermLoanMember_4d2b5b38-94aa-4052-a8eb-8bffd94c78e1" xlink:href="kwr-20240930.xsd#kwr_AmendedEuroTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_AmendedEuroTermLoanMember_4d2b5b38-94aa-4052-a8eb-8bffd94c78e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedUsTermLoanMember_0aa885b8-453e-438f-9cab-1d17e95e8fb5" xlink:href="kwr-20240930.xsd#kwr_AmendedUsTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_AmendedUsTermLoanMember_0aa885b8-453e-438f-9cab-1d17e95e8fb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedRevolverMember_45abc5bf-8791-457c-ad6f-a9bf7ba5b9f1" xlink:href="kwr-20240930.xsd#kwr_AmendedRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_AmendedRevolverMember_45abc5bf-8791-457c-ad6f-a9bf7ba5b9f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_AmendedCreditFacilityMember_f9fda56f-6262-4cac-b960-f0bc71383d73" xlink:href="kwr-20240930.xsd#kwr_AmendedCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_AmendedCreditFacilityMember_f9fda56f-6262-4cac-b960-f0bc71383d73" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_OriginalCreditFacilityAndTheAmendedCreditFacilityMember_85cc8da5-226a-48b2-8b22-69b2074e8739" xlink:href="kwr-20240930.xsd#kwr_OriginalCreditFacilityAndTheAmendedCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_OriginalCreditFacilityAndTheAmendedCreditFacilityMember_85cc8da5-226a-48b2-8b22-69b2074e8739" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_OldCreditFacilityMember_45a7c318-5d1b-4a97-9ae3-ecbdfaf40e06" xlink:href="kwr-20240930.xsd#kwr_OldCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_OldCreditFacilityMember_45a7c318-5d1b-4a97-9ae3-ecbdfaf40e06" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_ff48dbda-95ed-4b91-8ab3-a6b2dddfc007" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_ff48dbda-95ed-4b91-8ab3-a6b2dddfc007" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_BankLinesOfCreditAndOtherDebtObligationsMember_ece64294-6eee-427c-98f2-daa596d20afc" xlink:href="kwr-20240930.xsd#kwr_BankLinesOfCreditAndOtherDebtObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_kwr_BankLinesOfCreditAndOtherDebtObligationsMember_ece64294-6eee-427c-98f2-daa596d20afc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_2c4f19e2-2be1-4cb3-8f66-94e577db5d21" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3d90cadf-8f82-45fc-9775-6f17908618c4" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_2c4f19e2-2be1-4cb3-8f66-94e577db5d21" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_8e61a497-b421-4b63-a512-84ace02bf03c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:to="loc_srt_RangeAxis_8e61a497-b421-4b63-a512-84ace02bf03c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8e61a497-b421-4b63-a512-84ace02bf03c_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_8e61a497-b421-4b63-a512-84ace02bf03c" xlink:to="loc_srt_RangeMember_8e61a497-b421-4b63-a512-84ace02bf03c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_fd695bc2-edd2-4c73-8d63-0517a0336bb3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_8e61a497-b421-4b63-a512-84ace02bf03c" xlink:to="loc_srt_RangeMember_fd695bc2-edd2-4c73-8d63-0517a0336bb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_449d3be1-41dc-4279-aa09-84f9da1bca08" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_fd695bc2-edd2-4c73-8d63-0517a0336bb3" xlink:to="loc_srt_MaximumMember_449d3be1-41dc-4279-aa09-84f9da1bca08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_c7ca909b-e561-468d-ab69-dfc7031655ce" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_fd695bc2-edd2-4c73-8d63-0517a0336bb3" xlink:to="loc_srt_MinimumMember_c7ca909b-e561-468d-ab69-dfc7031655ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_8aa5c1e0-870d-4baa-9d63-1a08e3dba7c4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_8aa5c1e0-870d-4baa-9d63-1a08e3dba7c4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8aa5c1e0-870d-4baa-9d63-1a08e3dba7c4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_8aa5c1e0-870d-4baa-9d63-1a08e3dba7c4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8aa5c1e0-870d-4baa-9d63-1a08e3dba7c4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_81670b59-87f6-4c59-9556-e91f455f8f44" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_8aa5c1e0-870d-4baa-9d63-1a08e3dba7c4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_81670b59-87f6-4c59-9556-e91f455f8f44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_888e3add-aed5-4f0a-9822-c21afe49bb03" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_81670b59-87f6-4c59-9556-e91f455f8f44" xlink:to="loc_us-gaap_OtherAssetsMember_888e3add-aed5-4f0a-9822-c21afe49bb03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_4f454ad2-df24-40c3-b839-dfca03ef3376" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_4f454ad2-df24-40c3-b839-dfca03ef3376" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4f454ad2-df24-40c3-b839-dfca03ef3376_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4f454ad2-df24-40c3-b839-dfca03ef3376" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4f454ad2-df24-40c3-b839-dfca03ef3376_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_913f429b-a889-43ff-a18b-818c1dd96db0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4f454ad2-df24-40c3-b839-dfca03ef3376" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_913f429b-a889-43ff-a18b-818c1dd96db0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_6dcdd6ed-3404-43e0-9727-93513b2390be" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_913f429b-a889-43ff-a18b-818c1dd96db0" xlink:to="loc_us-gaap_InterestRateSwapMember_6dcdd6ed-3404-43e0-9727-93513b2390be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_965e629b-efcb-43d8-b720-332e11cd9254" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a02b256d-2088-4781-8803-c422d788cfec" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_965e629b-efcb-43d8-b720-332e11cd9254" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_965e629b-efcb-43d8-b720-332e11cd9254_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_965e629b-efcb-43d8-b720-332e11cd9254" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_965e629b-efcb-43d8-b720-332e11cd9254_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_c643ccaf-fe2d-4806-968b-b969e088d329" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_965e629b-efcb-43d8-b720-332e11cd9254" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_c643ccaf-fe2d-4806-968b-b969e088d329" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_0eb219ca-af77-4c09-b063-0f6c0925cb6a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_c643ccaf-fe2d-4806-968b-b969e088d329" xlink:to="loc_us-gaap_LetterOfCreditMember_0eb219ca-af77-4c09-b063-0f6c0925cb6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_aabe9b6d-4e52-419c-90ac-64e517aa22fd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_aabe9b6d-4e52-419c-90ac-64e517aa22fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_MaximumIncreaseInBorrowingCapacity_ce01afcf-be0f-4b9b-8eb8-53f480d4aeae" xlink:href="kwr-20240930.xsd#kwr_MaximumIncreaseInBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_kwr_MaximumIncreaseInBorrowingCapacity_ce01afcf-be0f-4b9b-8eb8-53f480d4aeae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_CreditFacilityAsPercentageOfConsolidatedEBITDA_c2cf87bf-87e7-4bf0-ac92-7ad71962f36b" xlink:href="kwr-20240930.xsd#kwr_CreditFacilityAsPercentageOfConsolidatedEBITDA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_kwr_CreditFacilityAsPercentageOfConsolidatedEBITDA_c2cf87bf-87e7-4bf0-ac92-7ad71962f36b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtWeightedAverageInterestRateOverTime_82009614-f47e-4749-b1e5-4c9a952f25ca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtWeightedAverageInterestRateOverTime"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LongTermDebtWeightedAverageInterestRateOverTime_82009614-f47e-4749-b1e5-4c9a952f25ca" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtPercentageBearingVariableInterestRate_30ccad18-9375-4285-b5d4-cca11b419e35" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtPercentageBearingVariableInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LongTermDebtPercentageBearingVariableInterestRate_30ccad18-9375-4285-b5d4-cca11b419e35" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_e527b675-a7b7-42c1-96a6-743e96dcecc9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_e527b675-a7b7-42c1-96a6-743e96dcecc9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_c6290c76-1f24-452e-8923-53f7ad947f87" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_c6290c76-1f24-452e-8923-53f7ad947f87" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_cbc1e06c-65d7-4ab1-bdc9-8d36bfdfb78d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_cbc1e06c-65d7-4ab1-bdc9-8d36bfdfb78d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_38ce5848-3f55-42ee-8ffb-2177bcd922ff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_38ce5848-3f55-42ee-8ffb-2177bcd922ff" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTermOfContract_7ca9fd1f-654f-4e66-96ee-d7d635a2192c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DerivativeTermOfContract_7ca9fd1f-654f-4e66-96ee-d7d635a2192c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_fb213ff2-c1a1-4f44-a365-0df23e8bde48" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_fb213ff2-c1a1-4f44-a365-0df23e8bde48" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeVariableInterestRate_28ffaa3c-d8e4-4672-bb0c-07de2c3d3ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeVariableInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DerivativeVariableInterestRate_28ffaa3c-d8e4-4672-bb0c-07de2c3d3ab3" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsCurrentNet_5c17c92b-a081-46a5-a48e-abaa9d7d38fb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredFinanceCostsCurrentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_DeferredFinanceCostsCurrentNet_5c17c92b-a081-46a5-a48e-abaa9d7d38fb" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtTerm_fea2bf1e-b43a-4c0d-8f7c-c73ae118cff7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LongTermDebtTerm_fea2bf1e-b43a-4c0d-8f7c-c73ae118cff7" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_Industrialdevelopmentrevenuebond_eb0103d8-d26b-4fc0-96fb-71b7ee3f441f" xlink:href="kwr-20240930.xsd#kwr_Industrialdevelopmentrevenuebond"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_kwr_Industrialdevelopmentrevenuebond_eb0103d8-d26b-4fc0-96fb-71b7ee3f441f" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_706e6237-97f9-42a0-8df2-75c098ec867f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9bb90502-bbd2-4075-8e05-9c80137577d5" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_706e6237-97f9-42a0-8df2-75c098ec867f" xlink:type="arc" order="15"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/AccumulatedOtherComprehensiveIncomeAOCIReclassificationsDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#AccumulatedOtherComprehensiveIncomeAOCIReclassificationsDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/AccumulatedOtherComprehensiveIncomeAOCIReclassificationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_23fc9833-018d-4aba-8e6b-9fc91a7a07ea" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_aae3f1f6-90a0-44d8-a0f5-64efdf3b2736" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_23fc9833-018d-4aba-8e6b-9fc91a7a07ea" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_aae3f1f6-90a0-44d8-a0f5-64efdf3b2736" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c51d1e1c-2e96-4c17-a986-9f8a91f39aff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_aae3f1f6-90a0-44d8-a0f5-64efdf3b2736" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c51d1e1c-2e96-4c17-a986-9f8a91f39aff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c51d1e1c-2e96-4c17-a986-9f8a91f39aff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c51d1e1c-2e96-4c17-a986-9f8a91f39aff" xlink:to="loc_us-gaap_EquityComponentDomain_c51d1e1c-2e96-4c17-a986-9f8a91f39aff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c51d1e1c-2e96-4c17-a986-9f8a91f39aff" xlink:to="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_f33749ce-2d26-4538-8b99-f7c6a10b9fb2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_f33749ce-2d26-4538-8b99-f7c6a10b9fb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_b89b3566-0501-4b03-818f-ba23a1da455d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_b89b3566-0501-4b03-818f-ba23a1da455d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_7f8d4ecd-3367-49d0-9004-86241dfc8deb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_7f8d4ecd-3367-49d0-9004-86241dfc8deb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_4e2aae06-34af-42ee-b48c-ab5822cd2c67" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_4e2aae06-34af-42ee-b48c-ab5822cd2c67" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_9ccba92b-3e61-4de9-983a-550a6932b847" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f54748f5-2e22-4f04-a1f3-48cd79dd1bcb" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_9ccba92b-3e61-4de9-983a-550a6932b847" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_f75f14fb-e825-4338-a5d6-a0bc7a82ca2a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_23fc9833-018d-4aba-8e6b-9fc91a7a07ea" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_f75f14fb-e825-4338-a5d6-a0bc7a82ca2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_907f1951-f43c-43c2-ac63-e67fa2f88bd5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_f75f14fb-e825-4338-a5d6-a0bc7a82ca2a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_907f1951-f43c-43c2-ac63-e67fa2f88bd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_20919349-a3fc-4ccc-a748-bfe3a49f3ecc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_f75f14fb-e825-4338-a5d6-a0bc7a82ca2a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_20919349-a3fc-4ccc-a748-bfe3a49f3ecc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_bc937717-42e3-4540-a35c-a6b1945c20ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_f75f14fb-e825-4338-a5d6-a0bc7a82ca2a" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_bc937717-42e3-4540-a35c-a6b1945c20ab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_c8ae1736-d193-4ad4-b452-6c8ed378eb3b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_f75f14fb-e825-4338-a5d6-a0bc7a82ca2a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_c8ae1736-d193-4ad4-b452-6c8ed378eb3b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_5d90c0b6-48e3-434b-ba16-45e5662bda77" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/HedgingActivitiesNotionalAmountsofNetForeignExchangeHedgePositionsDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#HedgingActivitiesNotionalAmountsofNetForeignExchangeHedgePositionsDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/HedgingActivitiesNotionalAmountsofNetForeignExchangeHedgePositionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_84947d35-2b8e-41ff-b687-266ba961bc0a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_e0e9add4-3f22-4a6a-8647-3418e9e9fd57" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_84947d35-2b8e-41ff-b687-266ba961bc0a" xlink:to="loc_us-gaap_DerivativeTable_e0e9add4-3f22-4a6a-8647-3418e9e9fd57" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CurrencyAxis_94da5d9f-1718-476f-84e2-2549de331b2c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CurrencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_e0e9add4-3f22-4a6a-8647-3418e9e9fd57" xlink:to="loc_srt_CurrencyAxis_94da5d9f-1718-476f-84e2-2549de331b2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_94da5d9f-1718-476f-84e2-2549de331b2c_default" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CurrencyAxis_94da5d9f-1718-476f-84e2-2549de331b2c" xlink:to="loc_currency_AllCurrenciesDomain_94da5d9f-1718-476f-84e2-2549de331b2c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_713035f3-b267-4d6f-9610-899f0ec9cd3d" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CurrencyAxis_94da5d9f-1718-476f-84e2-2549de331b2c" xlink:to="loc_currency_AllCurrenciesDomain_713035f3-b267-4d6f-9610-899f0ec9cd3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_MXN_108a7cab-a2b5-4dc7-a254-f8db5ec15a0f" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_MXN"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_713035f3-b267-4d6f-9610-899f0ec9cd3d" xlink:to="loc_currency_MXN_108a7cab-a2b5-4dc7-a254-f8db5ec15a0f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_JPY_3990e74e-31cf-4f25-ae30-4ac4e632008c" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_JPY"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_713035f3-b267-4d6f-9610-899f0ec9cd3d" xlink:to="loc_currency_JPY_3990e74e-31cf-4f25-ae30-4ac4e632008c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_1c765b42-7447-42e7-9e2b-1ddcc2fe4c2d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84947d35-2b8e-41ff-b687-266ba961bc0a" xlink:to="loc_us-gaap_DerivativeNotionalAmount_1c765b42-7447-42e7-9e2b-1ddcc2fe4c2d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/HedgingActivitiesNarrativeDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#HedgingActivitiesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/HedgingActivitiesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_e0edffd7-dd10-40f1-94c4-b7fbb3012556" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_d095ce56-40fc-411d-b82d-5871bb7d9549" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_e0edffd7-dd10-40f1-94c4-b7fbb3012556" xlink:to="loc_us-gaap_DerivativeTable_d095ce56-40fc-411d-b82d-5871bb7d9549" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_860a6099-f4c7-4fb8-b6c1-f860e6e23534" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_d095ce56-40fc-411d-b82d-5871bb7d9549" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_860a6099-f4c7-4fb8-b6c1-f860e6e23534" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_860a6099-f4c7-4fb8-b6c1-f860e6e23534_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_860a6099-f4c7-4fb8-b6c1-f860e6e23534" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_860a6099-f4c7-4fb8-b6c1-f860e6e23534_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_f054d300-7fe6-45b6-b3f4-b6dcca3e1fdd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_860a6099-f4c7-4fb8-b6c1-f860e6e23534" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_f054d300-7fe6-45b6-b3f4-b6dcca3e1fdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_651c7f3d-d049-4a32-9246-51cf5ab6746d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_f054d300-7fe6-45b6-b3f4-b6dcca3e1fdd" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_651c7f3d-d049-4a32-9246-51cf5ab6746d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_6ba38575-c187-40b2-9787-45fe4d02a402" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_f054d300-7fe6-45b6-b3f4-b6dcca3e1fdd" xlink:to="loc_us-gaap_InterestRateSwapMember_6ba38575-c187-40b2-9787-45fe4d02a402" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTermOfContract_54b4899e-4166-4a58-ab3e-1753c2a5e766" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_e0edffd7-dd10-40f1-94c4-b7fbb3012556" xlink:to="loc_us-gaap_DerivativeTermOfContract_54b4899e-4166-4a58-ab3e-1753c2a5e766" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_70cdf85d-5412-4ea3-831b-cb241c1491d6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_e0edffd7-dd10-40f1-94c4-b7fbb3012556" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_70cdf85d-5412-4ea3-831b-cb241c1491d6" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/HedgingActivitiesBalanceSheetClassificationandFairValuesDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#HedgingActivitiesBalanceSheetClassificationandFairValuesDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/HedgingActivitiesBalanceSheetClassificationandFairValuesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_93075b91-0239-4c5c-a062-77899800180d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_21c68a89-40db-4d91-a4a0-444556ca0ff5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_93075b91-0239-4c5c-a062-77899800180d" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_21c68a89-40db-4d91-a4a0-444556ca0ff5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_c5c2cb64-60ac-4d63-b493-f799dbde5e77" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_21c68a89-40db-4d91-a4a0-444556ca0ff5" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_c5c2cb64-60ac-4d63-b493-f799dbde5e77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c5c2cb64-60ac-4d63-b493-f799dbde5e77_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_c5c2cb64-60ac-4d63-b493-f799dbde5e77" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c5c2cb64-60ac-4d63-b493-f799dbde5e77_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_0be8bd20-e47f-4e57-b458-4bb967da5b9a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_c5c2cb64-60ac-4d63-b493-f799dbde5e77" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_0be8bd20-e47f-4e57-b458-4bb967da5b9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_3a8fbc6e-281f-4127-807f-7a365a7fbd7a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_0be8bd20-e47f-4e57-b458-4bb967da5b9a" xlink:to="loc_us-gaap_InterestRateSwapMember_3a8fbc6e-281f-4127-807f-7a365a7fbd7a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_ef388058-6246-4d14-a567-a2532b220af6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_0be8bd20-e47f-4e57-b458-4bb967da5b9a" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_ef388058-6246-4d14-a567-a2532b220af6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_8dc95fff-d1d2-44e0-a2c1-0f8d6d928104" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_21c68a89-40db-4d91-a4a0-444556ca0ff5" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_8dc95fff-d1d2-44e0-a2c1-0f8d6d928104" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8dc95fff-d1d2-44e0-a2c1-0f8d6d928104_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_8dc95fff-d1d2-44e0-a2c1-0f8d6d928104" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8dc95fff-d1d2-44e0-a2c1-0f8d6d928104_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_a5cfcc3e-1ad9-41a2-ba3e-1cb163b73329" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_8dc95fff-d1d2-44e0-a2c1-0f8d6d928104" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_a5cfcc3e-1ad9-41a2-ba3e-1cb163b73329" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_f1b3ad03-ab84-4b8d-b100-c30be0e62567" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_a5cfcc3e-1ad9-41a2-ba3e-1cb163b73329" xlink:to="loc_us-gaap_InterestExpenseMember_f1b3ad03-ab84-4b8d-b100-c30be0e62567" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseMember_5aea8753-0c28-4952-8d82-0d6537af1df4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_a5cfcc3e-1ad9-41a2-ba3e-1cb163b73329" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseMember_5aea8753-0c28-4952-8d82-0d6537af1df4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationAxis_ea9d00e9-4f17-4895-acae-8cdfb46ebffe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_21c68a89-40db-4d91-a4a0-444556ca0ff5" xlink:to="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationAxis_ea9d00e9-4f17-4895-acae-8cdfb46ebffe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain_ea9d00e9-4f17-4895-acae-8cdfb46ebffe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationAxis_ea9d00e9-4f17-4895-acae-8cdfb46ebffe" xlink:to="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain_ea9d00e9-4f17-4895-acae-8cdfb46ebffe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain_fc61e50b-ee56-4b23-8bd1-f0ec7112e21d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationAxis_ea9d00e9-4f17-4895-acae-8cdfb46ebffe" xlink:to="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain_fc61e50b-ee56-4b23-8bd1-f0ec7112e21d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_17dfb5c5-99a1-4329-aec7-8cd11b402eef" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain_fc61e50b-ee56-4b23-8bd1-f0ec7112e21d" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_17dfb5c5-99a1-4329-aec7-8cd11b402eef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_75e133b2-c919-4b53-81a5-5ce23beba5df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementOfFinancialPositionLocationActivityCapitalizationDomain_fc61e50b-ee56-4b23-8bd1-f0ec7112e21d" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_75e133b2-c919-4b53-81a5-5ce23beba5df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_51553114-7a5e-427b-b7ce-e7467e9c8a82" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_93075b91-0239-4c5c-a062-77899800180d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_51553114-7a5e-427b-b7ce-e7467e9c8a82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_71b54670-bae9-417c-bce4-78efc7dd9cad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_93075b91-0239-4c5c-a062-77899800180d" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_71b54670-bae9-417c-bce4-78efc7dd9cad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_fb59685e-0dae-43a0-936e-b176826424e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_93075b91-0239-4c5c-a062-77899800180d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_fb59685e-0dae-43a0-936e-b176826424e5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.quakerchem.com/role/CommitmentsandContingenciesDetails" xlink:type="simple" xlink:href="kwr-20240930.xsd#CommitmentsandContingenciesDetails"/>
  <link:definitionLink xlink:role="http://www.quakerchem.com/role/CommitmentsandContingenciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_690a4abd-8354-4ea9-915e-1979383b4bc8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_d2c7b104-7a2e-4659-9cf0-edaf79da79e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_690a4abd-8354-4ea9-915e-1979383b4bc8" xlink:to="loc_us-gaap_LossContingenciesTable_d2c7b104-7a2e-4659-9cf0-edaf79da79e4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_adb99766-779f-46ef-97c3-0845dd585fbd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_d2c7b104-7a2e-4659-9cf0-edaf79da79e4" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_adb99766-779f-46ef-97c3-0845dd585fbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_adb99766-779f-46ef-97c3-0845dd585fbd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_adb99766-779f-46ef-97c3-0845dd585fbd" xlink:to="loc_us-gaap_LossContingencyNatureDomain_adb99766-779f-46ef-97c3-0845dd585fbd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_eeac2dd9-b1d5-445c-832f-94d9b478e2e6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_adb99766-779f-46ef-97c3-0845dd585fbd" xlink:to="loc_us-gaap_LossContingencyNatureDomain_eeac2dd9-b1d5-445c-832f-94d9b478e2e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_HoughtonEnvironmentalMattersMember_afd3430f-1b3b-4728-ba3e-0bf40898701f" xlink:href="kwr-20240930.xsd#kwr_HoughtonEnvironmentalMattersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_eeac2dd9-b1d5-445c-832f-94d9b478e2e6" xlink:to="loc_kwr_HoughtonEnvironmentalMattersMember_afd3430f-1b3b-4728-ba3e-0bf40898701f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_f57949df-e6a6-4822-a78b-8d9bd4dcd7df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_d2c7b104-7a2e-4659-9cf0-edaf79da79e4" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_f57949df-e6a6-4822-a78b-8d9bd4dcd7df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f57949df-e6a6-4822-a78b-8d9bd4dcd7df_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_f57949df-e6a6-4822-a78b-8d9bd4dcd7df" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f57949df-e6a6-4822-a78b-8d9bd4dcd7df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_52b6a573-33a8-48bf-8d24-e6b74f6376f7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_f57949df-e6a6-4822-a78b-8d9bd4dcd7df" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_52b6a573-33a8-48bf-8d24-e6b74f6376f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_CoralChemicalCompanyMember_e43b56eb-68bc-45e2-99a1-2b9e0c5be5aa" xlink:href="kwr-20240930.xsd#kwr_CoralChemicalCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_52b6a573-33a8-48bf-8d24-e6b74f6376f7" xlink:to="loc_kwr_CoralChemicalCompanyMember_e43b56eb-68bc-45e2-99a1-2b9e0c5be5aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_430aad4f-bff7-47b0-826a-901ba273e9e6" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_d2c7b104-7a2e-4659-9cf0-edaf79da79e4" xlink:to="loc_srt_RangeAxis_430aad4f-bff7-47b0-826a-901ba273e9e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_430aad4f-bff7-47b0-826a-901ba273e9e6_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_430aad4f-bff7-47b0-826a-901ba273e9e6" xlink:to="loc_srt_RangeMember_430aad4f-bff7-47b0-826a-901ba273e9e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b611443e-39a0-4997-a345-8ec8d36dcb8c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_430aad4f-bff7-47b0-826a-901ba273e9e6" xlink:to="loc_srt_RangeMember_b611443e-39a0-4997-a345-8ec8d36dcb8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_6540a729-32a8-4338-93d3-4d3e211d7a75" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_b611443e-39a0-4997-a345-8ec8d36dcb8c" xlink:to="loc_srt_MinimumMember_6540a729-32a8-4338-93d3-4d3e211d7a75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_5a142547-41bd-4af9-9511-86ac3777961c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_b611443e-39a0-4997-a345-8ec8d36dcb8c" xlink:to="loc_srt_MaximumMember_5a142547-41bd-4af9-9511-86ac3777961c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_92b798c8-f789-4ec7-a4e4-46c44391eeef" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_690a4abd-8354-4ea9-915e-1979383b4bc8" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_92b798c8-f789-4ec7-a4e4-46c44391eeef" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_StockOptionsCompensationExpenseMember_c8917fe0-3bf0-4d7d-bd5a-8424c5a8d9f6" xlink:href="kwr-20240930.xsd#kwr_StockOptionsCompensationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_kwr_StockOptionsCompensationExpenseMember_c8917fe0-3bf0-4d7d-bd5a-8424c5a8d9f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_NonvestedStockAwardsCompensationExpenseMember_016ca160-1612-4e31-b8a4-368671ba810f" xlink:href="kwr-20240930.xsd#kwr_NonvestedStockAwardsCompensationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_kwr_NonvestedStockAwardsCompensationExpenseMember_016ca160-1612-4e31-b8a4-368671ba810f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_DirectorsStockOwnershipPlanCompensationExpenseMember_b5954c6a-af62-4986-a055-06a6b2541b78" xlink:href="kwr-20240930.xsd#kwr_DirectorsStockOwnershipPlanCompensationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_kwr_DirectorsStockOwnershipPlanCompensationExpenseMember_b5954c6a-af62-4986-a055-06a6b2541b78" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_PerformanceSharesMember" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockMember" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_PerformanceStockUnitsROICMember_be059561-8f3c-413f-af95-dd966869c391" xlink:href="kwr-20240930.xsd#kwr_PerformanceStockUnitsROICMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_kwr_PerformanceStockUnitsROICMember_be059561-8f3c-413f-af95-dd966869c391" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_kwr_PerformanceStockUnitsTSRMember_bdfaa1ff-6a8c-40c6-9c2c-a9fdebd7e184" xlink:href="kwr-20240930.xsd#kwr_PerformanceStockUnitsTSRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_kwr_PerformanceStockUnitsTSRMember_bdfaa1ff-6a8c-40c6-9c2c-a9fdebd7e184" xlink:type="arc" order="10"/>
  </link:definitionLink>
</link:linkbase>
