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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:6fc9a05f-9361-422e-9e55-15ab55e30a25,g:16bb36fb-f001-42da-9db7-4505f9b0afb3-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:oln="http://www.olin.com/20250930" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types1="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2022-03-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.olin.com/20250930">
  <xs:import namespace="http://fasb.org/srt/2024" schemaLocation="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2024" schemaLocation="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2022-03-31" schemaLocation="https://www.xbrl.org/dtr/type/2022-03-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2024" schemaLocation="https://xbrl.sec.gov/country/2024/country-2024.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2024" schemaLocation="https://xbrl.sec.gov/dei/2024/dei-2024.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2024" schemaLocation="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="oln-20250930_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="oln-20250930_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="oln-20250930_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="oln-20250930_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="DocumentAndEntityInformation" roleURI="http://www.olin.com/role/DocumentAndEntityInformation">
        <link:definition>0000001 - Document - Document And Entity Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDBALANCESHEETS" roleURI="http://www.olin.com/role/CONDENSEDBALANCESHEETS">
        <link:definition>9952151 - Statement - CONDENSED BALANCE SHEETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDESNEDBALANCESHEETSPARENTHETICAL" roleURI="http://www.olin.com/role/CONDESNEDBALANCESHEETSPARENTHETICAL">
        <link:definition>9952152 - Statement - CONDESNED BALANCE SHEETS PARENTHETICAL</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDSTATEMENTOFOPERATIONS" roleURI="http://www.olin.com/role/CONDENSEDSTATEMENTOFOPERATIONS">
        <link:definition>9952153 - Statement - CONDENSED STATEMENT OF OPERATIONS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" roleURI="http://www.olin.com/role/CONDENSEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS">
        <link:definition>9952154 - Statement - CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDSTATEMENTSOFSHAREHOLDERSEQUITY" roleURI="http://www.olin.com/role/CONDENSEDSTATEMENTSOFSHAREHOLDERSEQUITY">
        <link:definition>9952155 - Statement - CONDENSED STATEMENTS OF SHAREHOLDERS' EQUITY</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDSTATEMENTSOFCASHFLOWS" roleURI="http://www.olin.com/role/CONDENSEDSTATEMENTSOFCASHFLOWS">
        <link:definition>9952156 - Statement - CONDENSED STATEMENTS OF CASH FLOWS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DESCRIPTIONOFBUSINESS" roleURI="http://www.olin.com/role/DESCRIPTIONOFBUSINESS">
        <link:definition>9952157 - Disclosure - DESCRIPTION OF BUSINESS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RECENTACCOUNTINGPRONOUNCEMENTS" roleURI="http://www.olin.com/role/RECENTACCOUNTINGPRONOUNCEMENTS">
        <link:definition>9952158 - Disclosure - RECENT ACCOUNTING PRONOUNCEMENTS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACQUISITIONS" roleURI="http://www.olin.com/role/ACQUISITIONS">
        <link:definition>9952159 - Disclosure - ACQUISITIONS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGES" roleURI="http://www.olin.com/role/RESTRUCTURINGCHARGES">
        <link:definition>9952160 - Disclosure - RESTRUCTURING CHARGES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EARNINGSPERSHARE" roleURI="http://www.olin.com/role/EARNINGSPERSHARE">
        <link:definition>9952161 - Disclosure - EARNINGS PER SHARE</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCOUNTSRECEIVABLES" roleURI="http://www.olin.com/role/ACCOUNTSRECEIVABLES">
        <link:definition>9952162 - Disclosure - ACCOUNTS RECEIVABLES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIES" roleURI="http://www.olin.com/role/INVENTORIES">
        <link:definition>9952163 - Disclosure - INVENTORIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHERASSETS" roleURI="http://www.olin.com/role/OTHERASSETS">
        <link:definition>9952164 - Disclosure - OTHER ASSETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETS" roleURI="http://www.olin.com/role/GOODWILLANDINTANGIBLEASSETS">
        <link:definition>9952165 - Disclosure - GOODWILL AND INTANGIBLE ASSETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBT" roleURI="http://www.olin.com/role/DEBT">
        <link:definition>9952166 - Disclosure - DEBT</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PENSIONPLANSANDRETIREMENTBENEFITS" roleURI="http://www.olin.com/role/PENSIONPLANSANDRETIREMENTBENEFITS">
        <link:definition>9952167 - Disclosure - PENSION PLANS AND RETIREMENT BENEFITS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXES" roleURI="http://www.olin.com/role/INCOMETAXES">
        <link:definition>9952168 - Disclosure - INCOME TAXES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEFINEDCONTRIBUTIONPLAN" roleURI="http://www.olin.com/role/DEFINEDCONTRIBUTIONPLAN">
        <link:definition>9952169 - Disclosure - DEFINED CONTRIBUTION PLAN</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKBASEDCOMPENSATION" roleURI="http://www.olin.com/role/STOCKBASEDCOMPENSATION">
        <link:definition>9952170 - Disclosure - STOCK-BASED COMPENSATION</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SHAREHOLDERSEQUITY" roleURI="http://www.olin.com/role/SHAREHOLDERSEQUITY">
        <link:definition>9952171 - Disclosure - SHAREHOLDERS' EQUITY</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATION" roleURI="http://www.olin.com/role/SEGMENTINFORMATION">
        <link:definition>9952172 - Disclosure - SEGMENT INFORMATION</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ENVIRONMENTAL" roleURI="http://www.olin.com/role/ENVIRONMENTAL">
        <link:definition>9952173 - Disclosure - ENVIRONMENTAL</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="COMMITMENTSANDCONTINGENCIES" roleURI="http://www.olin.com/role/COMMITMENTSANDCONTINGENCIES">
        <link:definition>9952174 - Disclosure - COMMITMENTS AND CONTINGENCIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DERIVATIVEFINANCIALINSTRUMENTS" roleURI="http://www.olin.com/role/DERIVATIVEFINANCIALINSTRUMENTS">
        <link:definition>9952175 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTS" roleURI="http://www.olin.com/role/FAIRVALUEMEASUREMENTS">
        <link:definition>9952176 - Disclosure - FAIR VALUE MEASUREMENTS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESTables" roleURI="http://www.olin.com/role/RESTRUCTURINGCHARGESTables">
        <link:definition>9955511 - Disclosure - RESTRUCTURING CHARGES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EARNINGSPERSHARETables" roleURI="http://www.olin.com/role/EARNINGSPERSHARETables">
        <link:definition>9955512 - Disclosure - EARNINGS PER SHARE (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCOUNTSRECEIVABLESTables" roleURI="http://www.olin.com/role/ACCOUNTSRECEIVABLESTables">
        <link:definition>9955513 - Disclosure - ACCOUNTS RECEIVABLES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESTables" roleURI="http://www.olin.com/role/INVENTORIESTables">
        <link:definition>9955514 - Disclosure - INVENTORIES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHERASSETSTables" roleURI="http://www.olin.com/role/OTHERASSETSTables">
        <link:definition>9955515 - Disclosure - OTHER ASSETS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSTables" roleURI="http://www.olin.com/role/GOODWILLANDINTANGIBLEASSETSTables">
        <link:definition>9955516 - Disclosure - GOODWILL AND INTANGIBLE ASSETS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTTables" roleURI="http://www.olin.com/role/DEBTTables">
        <link:definition>9955517 - Disclosure - DEBT (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PENSIONPLANSANDRETIREMENTBENEFITSTables" roleURI="http://www.olin.com/role/PENSIONPLANSANDRETIREMENTBENEFITSTables">
        <link:definition>9955518 - Disclosure - PENSION PLANS AND RETIREMENT BENEFITS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXESTables" roleURI="http://www.olin.com/role/INCOMETAXESTables">
        <link:definition>9955519 - Disclosure - INCOME TAXES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEFINEDCONTRIBUTIONPLANTables" roleURI="http://www.olin.com/role/DEFINEDCONTRIBUTIONPLANTables">
        <link:definition>9955520 - Disclosure - DEFINED CONTRIBUTION PLAN (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKBASEDCOMPENSATIONTables" roleURI="http://www.olin.com/role/STOCKBASEDCOMPENSATIONTables">
        <link:definition>9955521 - Disclosure - STOCK-BASED COMPENSATION (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SHAREHOLDERSEQUITYTables" roleURI="http://www.olin.com/role/SHAREHOLDERSEQUITYTables">
        <link:definition>9955522 - Disclosure - SHAREHOLDERS' EQUITY (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONTables" roleURI="http://www.olin.com/role/SEGMENTINFORMATIONTables">
        <link:definition>9955523 - Disclosure - SEGMENT INFORMATION (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ENVIRONMENTALREMEDIATIONOBLIGATIONSTables" roleURI="http://www.olin.com/role/ENVIRONMENTALREMEDIATIONOBLIGATIONSTables">
        <link:definition>9955524 - Disclosure - ENVIRONMENTAL REMEDIATION OBLIGATIONS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DERIVATIVEFINANCIALINSTRUMENTSTables" roleURI="http://www.olin.com/role/DERIVATIVEFINANCIALINSTRUMENTSTables">
        <link:definition>9955525 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RECENTACCOUNTINGPRONOUNCEMENTSDetails" roleURI="http://www.olin.com/role/RECENTACCOUNTINGPRONOUNCEMENTSDetails">
        <link:definition>9955526 - Disclosure - RECENT ACCOUNTING PRONOUNCEMENTS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACQUISITIONSDetails" roleURI="http://www.olin.com/role/ACQUISITIONSDetails">
        <link:definition>9955527 - Disclosure - ACQUISITIONS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESDetails1" roleURI="http://www.olin.com/role/RESTRUCTURINGCHARGESDetails1">
        <link:definition>9955528 - Disclosure - RESTRUCTURING CHARGES (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESDetails2" roleURI="http://www.olin.com/role/RESTRUCTURINGCHARGESDetails2">
        <link:definition>9955529 - Disclosure - RESTRUCTURING CHARGES (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RESTRUCTURINGCHARGESDetails3" roleURI="http://www.olin.com/role/RESTRUCTURINGCHARGESDetails3">
        <link:definition>9955530 - Disclosure - RESTRUCTURING CHARGES (Details 3)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EARNINGSPERSHAREDetails" roleURI="http://www.olin.com/role/EARNINGSPERSHAREDetails">
        <link:definition>9955531 - Disclosure - EARNINGS PER SHARE (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCOUNTSRECEIVABLESDetails" roleURI="http://www.olin.com/role/ACCOUNTSRECEIVABLESDetails">
        <link:definition>9955532 - Disclosure - ACCOUNTS RECEIVABLES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESDetails" roleURI="http://www.olin.com/role/INVENTORIESDetails">
        <link:definition>9955533 - Disclosure - INVENTORIES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OTHERASSETSDetails" roleURI="http://www.olin.com/role/OTHERASSETSDetails">
        <link:definition>9955534 - Disclosure - OTHER ASSETS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSDetails1" roleURI="http://www.olin.com/role/GOODWILLANDINTANGIBLEASSETSDetails1">
        <link:definition>9955535 - Disclosure - GOODWILL AND INTANGIBLE ASSETS (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSDetails2" roleURI="http://www.olin.com/role/GOODWILLANDINTANGIBLEASSETSDetails2">
        <link:definition>9955536 - Disclosure - GOODWILL AND INTANGIBLE ASSETS (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTDetails1" roleURI="http://www.olin.com/role/DEBTDetails1">
        <link:definition>9955537 - Disclosure - DEBT (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTDetails2" roleURI="http://www.olin.com/role/DEBTDetails2">
        <link:definition>9955538 - Disclosure - DEBT (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PENSIONPLANSANDRETIREMENTBENEFITSDetails1" roleURI="http://www.olin.com/role/PENSIONPLANSANDRETIREMENTBENEFITSDetails1">
        <link:definition>9955539 - Disclosure - PENSION PLANS AND RETIREMENT BENEFITS (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXESDetails1" roleURI="http://www.olin.com/role/INCOMETAXESDetails1">
        <link:definition>9955540 - Disclosure - INCOME TAXES (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXESDetails2" roleURI="http://www.olin.com/role/INCOMETAXESDetails2">
        <link:definition>9955541 - Disclosure - INCOME TAXES (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEFINEDCONTRIBUTIONPLANDetails" roleURI="http://www.olin.com/role/DEFINEDCONTRIBUTIONPLANDetails">
        <link:definition>9955542 - Disclosure - DEFINED CONTRIBUTION PLAN (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKBASEDCOMPENSATIONDetails1" roleURI="http://www.olin.com/role/STOCKBASEDCOMPENSATIONDetails1">
        <link:definition>9955543 - Disclosure - STOCK-BASED COMPENSATION (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKBASEDCOMPENSATIONDetails2" roleURI="http://www.olin.com/role/STOCKBASEDCOMPENSATIONDetails2">
        <link:definition>9955544 - Disclosure - STOCK-BASED COMPENSATION (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SHAREHOLDERSEQUITYDetails" roleURI="http://www.olin.com/role/SHAREHOLDERSEQUITYDetails">
        <link:definition>9955545 - Disclosure - SHAREHOLDERS' EQUITY (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONDetails1" roleURI="http://www.olin.com/role/SEGMENTINFORMATIONDetails1">
        <link:definition>9955546 - Disclosure - SEGMENT INFORMATION (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONDetails2" roleURI="http://www.olin.com/role/SEGMENTINFORMATIONDetails2">
        <link:definition>9955547 - Disclosure - SEGMENT INFORMATION (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ENVIRONMENTALDetails" roleURI="http://www.olin.com/role/ENVIRONMENTALDetails">
        <link:definition>9955548 - Disclosure - ENVIRONMENTAL (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="COMMITMENTSANDCONTINGENCIESDetails" roleURI="http://www.olin.com/role/COMMITMENTSANDCONTINGENCIESDetails">
        <link:definition>9955549 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DERIVATIVEFINANCIALINSTRUMENTSDetailsTextuals" roleURI="http://www.olin.com/role/DERIVATIVEFINANCIALINSTRUMENTSDetailsTextuals">
        <link:definition>9955550 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details Textuals)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DERIVATIVEFINANCIALINSTRUMENTSDetails1" roleURI="http://www.olin.com/role/DERIVATIVEFINANCIALINSTRUMENTSDetails1">
        <link:definition>9955551 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details 1)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DERIVATIVEFINANCIALINSTRUMENTSDetails2" roleURI="http://www.olin.com/role/DERIVATIVEFINANCIALINSTRUMENTSDetails2">
        <link:definition>9955552 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details 2)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DERIVATIVEFINANCIALINSTRUMENTSDetails3" roleURI="http://www.olin.com/role/DERIVATIVEFINANCIALINSTRUMENTSDetails3">
        <link:definition>9955553 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details 3)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FAIRVALUEMEASUREMENTSDetails" roleURI="http://www.olin.com/role/FAIRVALUEMEASUREMENTSDetails">
        <link:definition>9955554 - Disclosure - FAIR VALUE MEASUREMENTS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="oln_NetIncomeLossOfNonConsolidatedAffiliate" abstract="false" name="NetIncomeLossOfNonConsolidatedAffiliate" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_LossOfNonConsolidatedAffiliate" abstract="false" name="LossOfNonConsolidatedAffiliate" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_PensionIncomeExpense" abstract="false" name="PensionIncomeExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_LongTermOtherSupplyContractPayments" abstract="false" name="LongTermOtherSupplyContractPayments" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_IncreaseDecreaseinCapitalExpendituresIncurredbutNotYetPaid" abstract="false" name="IncreaseDecreaseinCapitalExpendituresIncurredbutNotYetPaid" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_ScheduleOfShareBasedPaymentAwardPerformanceShareAwardsValuationAssumptionsTableTextBlock" abstract="false" name="ScheduleOfShareBasedPaymentAwardPerformanceShareAwardsValuationAssumptionsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="oln_EnvironmentalExpenseChargedToIncomeTableTextBlock" abstract="false" name="EnvironmentalExpenseChargedToIncomeTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="oln_AMMOInc.Member" abstract="true" name="AMMOInc.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_EpoxySegmentMember" abstract="true" name="EpoxySegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_ChlorAlkaliProductsandVinylsSegmentMember" abstract="true" name="ChlorAlkaliProductsandVinylsSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_McIntoshRestructuringCapacityReduction" abstract="false" name="McIntoshRestructuringCapacityReduction" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:massItemType"/>
  <xs:element id="oln_FreeportChlorAlkaliCapacityReduction" abstract="false" name="FreeportChlorAlkaliCapacityReduction" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:massItemType"/>
  <xs:element id="oln_WriteoffofEquipmentandFacilityMember" abstract="true" name="WriteoffofEquipmentandFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_FacilityExitCostsAssetRetirementObligationsMember" abstract="true" name="FacilityExitCostsAssetRetirementObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_WinchesterSegmentMember" abstract="true" name="WinchesterSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_SupplyContracts" abstract="false" name="SupplyContracts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_AmortizationofSupplyContracts" abstract="false" name="AmortizationofSupplyContracts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_NilicoHydrogenHoldingsLLCMember" abstract="true" name="NilicoHydrogenHoldingsLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_PLugPowerLALLCMember" abstract="true" name="PLugPowerLALLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_HidrogeniiMember" abstract="true" name="HidrogeniiMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassTable" abstract="true" name="ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="oln_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassLineItems" abstract="true" name="ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oln_A9.5SeniorNoteMember" abstract="true" name="A9.5SeniorNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A5.125SeniorNoteMember" abstract="true" name="A5.125SeniorNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A5.625SeniorNoteMember" abstract="true" name="A5.625SeniorNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A5.00SeniorNoteMember" abstract="true" name="A5.00SeniorNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A6.625SeniorNoteMember" abstract="true" name="A6.625SeniorNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_VariableRateTermLoanMember" abstract="true" name="VariableRateTermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_VariableRateSeniorRevolvingFacilityMember" abstract="true" name="VariableRateSeniorRevolvingFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_VariableRateRecoveryZoneBondsMember" abstract="true" name="VariableRateRecoveryZoneBondsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_VariableRateIndustrialAndEnvironmentalObligationsMember" abstract="true" name="VariableRateIndustrialAndEnvironmentalObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A1850.0MillionSecuredCreditFacilityMember" abstract="true" name="A1850.0MillionSecuredCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A2025SeniorTermLoanMember" abstract="true" name="A2025SeniorTermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A9.5SeniorNoteBeforePaydownMember" abstract="true" name="A9.5SeniorNoteBeforePaydownMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A5.125SeniorNoteBeforePaydownMember" abstract="true" name="A5.125SeniorNoteBeforePaydownMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A2022SeniorTermLoanMember" abstract="true" name="A2022SeniorTermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_ReceivablesFinancingAgreementMember" abstract="true" name="ReceivablesFinancingAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A2025SeniorCreditFacility" abstract="false" name="A2025SeniorCreditFacility" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_A2025SeniorCreditFacilityIncrease" abstract="false" name="A2025SeniorCreditFacilityIncrease" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_QuarterlyRequiredPrincipalPaymentPercentThrough2027" abstract="false" name="QuarterlyRequiredPrincipalPaymentPercentThrough2027" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="oln_QuarterlyRequiredPrincipalPaymentPercentAfter2027" abstract="false" name="QuarterlyRequiredPrincipalPaymentPercentAfter2027" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="oln_SecuredBorrowingMaximumCapacity" abstract="false" name="SecuredBorrowingMaximumCapacity" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_SecuredBorrowingMaximumCapacityBorrowingLimit" abstract="false" name="SecuredBorrowingMaximumCapacityBorrowingLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_SecuredBorrowingMaximumCapacityIncrease" abstract="false" name="SecuredBorrowingMaximumCapacityIncrease" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_TradeReceivablesPledgedAsCollateralForSecuredBorrowings" abstract="false" name="TradeReceivablesPledgedAsCollateralForSecuredBorrowings" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_ReceivablesFinancingAvailableBorrowingCapacity" abstract="false" name="ReceivablesFinancingAvailableBorrowingCapacity" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_VariableRateGoZoneBondsMember" abstract="true" name="VariableRateGoZoneBondsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_A15500MillionSecuredCreditFacilityMember" abstract="true" name="A15500MillionSecuredCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A3500MillionTermLoanFacilityMember" abstract="true" name="A3500MillionTermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A12000MillionSeniorRevolvingCreditFacilityMember" abstract="true" name="A12000MillionSeniorRevolvingCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_LettersOfCreditIssuedUnderSeniorRevolvingCreditFacilityMember" abstract="true" name="LettersOfCreditIssuedUnderSeniorRevolvingCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A505.0MillionOfBorrowingsUnderSecuredCreditFacilityMember" abstract="true" name="A505.0MillionOfBorrowingsUnderSecuredCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_SeniorRevolvingCreditFacilityMember" abstract="true" name="SeniorRevolvingCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A2022SeniorCreditFacility" abstract="false" name="A2022SeniorCreditFacility" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_TermLoanFacilityMaximumBorrowingCapacity" abstract="false" name="TermLoanFacilityMaximumBorrowingCapacity" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_EffectiveTaxRateDiscreteItemsnetPercent" abstract="false" name="EffectiveTaxRateDiscreteItemsnetPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="oln_HidrogeniiJVTable" abstract="true" name="HidrogeniiJVTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="oln_HidrogeniiJVAxis" abstract="true" name="HidrogeniiJVAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oln_HidrogeniiJVDomain" abstract="true" name="HidrogeniiJVDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_HidrogeniiJVLineItems" abstract="true" name="HidrogeniiJVLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oln_ContributionToIndividualRetirementAccountPercentageOfEmployeesEligibleCompensation" abstract="false" name="ContributionToIndividualRetirementAccountPercentageOfEmployeesEligibleCompensation" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="oln_DefinedContributionPlanEmployerContributionOfEligibleCompensation" abstract="false" name="DefinedContributionPlanEmployerContributionOfEligibleCompensation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_TotalDefinedContributionPlanExpense" abstract="false" name="TotalDefinedContributionPlanExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarkToMarketAdjustment" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardMarkToMarketAdjustment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_ShareBasedCompensationArrangementByShareBasedPaymentAwardTotalExpense" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardTotalExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_ModelTypeAxis" abstract="true" name="ModelTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oln_ModelTypeDomain" abstract="true" name="ModelTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_MonteCarloSimulationModelMember" abstract="true" name="MonteCarloSimulationModelMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_BlackSholesOptionPricingModelMember" abstract="true" name="BlackSholesOptionPricingModelMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_PerformanceShareAwardTotalShareholderReturnPercent" abstract="false" name="PerformanceShareAwardTotalShareholderReturnPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="oln_PerformanceShareAwardCycle" abstract="false" name="PerformanceShareAwardCycle" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType"/>
  <xs:element id="oln_PerformanceShareAwardNetIncomePercent" abstract="false" name="PerformanceShareAwardNetIncomePercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="oln_ShareBasedCompensationArrangementsExpectedVolatilityRateOfPeerCompanies" abstract="false" name="ShareBasedCompensationArrangementsExpectedVolatilityRateOfPeerCompanies" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="oln_ShareBasedCompensationAverageCorrelationCoefficientOfPeerCompanies" abstract="false" name="ShareBasedCompensationAverageCorrelationCoefficientOfPeerCompanies" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="oln_PerformanceShareAwardTotalShareholderReturnFV" abstract="false" name="PerformanceShareAwardTotalShareholderReturnFV" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_PerformanceShareAwardNetIncomeFV" abstract="false" name="PerformanceShareAwardNetIncomeFV" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_PerformanceShareAwardsSharesGranted" abstract="false" name="PerformanceShareAwardsSharesGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="oln_A2022ShareRepurchaseProgramMember" abstract="true" name="A2022ShareRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_A2024ShareRepurchaseProgramMember" abstract="true" name="A2024ShareRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_ForeignCurrencyTranslationAdjustmentRollForward" abstract="true" name="ForeignCurrencyTranslationAdjustmentRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oln_UnrealizedGainsLossesOnDerivativeContractsSummaryRollForward" abstract="true" name="UnrealizedGainsLossesOnDerivativeContractsSummaryRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oln_PensionAndPostretirementBenefitsSummaryRollForward" abstract="true" name="PensionAndPostretirementBenefitsSummaryRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oln_AccumulatedOtherComprehensiveLossRollForward" abstract="true" name="AccumulatedOtherComprehensiveLossRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oln_OtherComprehensiveIncomeLossNetGainLossRecognizedBeforeTax" abstract="false" name="OtherComprehensiveIncomeLossNetGainLossRecognizedBeforeTax" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_OtherComprehensiveIncomeLossReclassificationAdjustmentBeforeTax" abstract="false" name="OtherComprehensiveIncomeLossReclassificationAdjustmentBeforeTax" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_CorporateOtherMember" abstract="true" name="CorporateOtherMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oln_OtherforeignMember" abstract="true" name="OtherforeignMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_NonOperatingPensionIncome" abstract="false" name="NonOperatingPensionIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oln_CausticsodaMember" abstract="true" name="CausticsodaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_ChlorinechlorinederivativesandothercoproductsMember" abstract="true" name="ChlorinechlorinederivativesandothercoproductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_AromaticsandallylicsMember" abstract="true" name="AromaticsandallylicsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_EpoxyresinsMember" abstract="true" name="EpoxyresinsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_CommercialMember" abstract="true" name="CommercialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_MilitaryandlawenforcementMember" abstract="true" name="MilitaryandlawenforcementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_ForwardContractsBuyMember" abstract="true" name="ForwardContractsBuyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_ForwardContractsSellMember" abstract="true" name="ForwardContractsSellMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_NaturalGasCommodityForwardContractsMember" abstract="true" name="NaturalGasCommodityForwardContractsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_MetalsCommodityForwardContractsMember" abstract="true" name="MetalsCommodityForwardContractsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_CommodityContractsGainsMember" abstract="true" name="CommodityContractsGainsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_ForeignExchangeContractGainMember" abstract="true" name="ForeignExchangeContractGainMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_CommodityContractsLossesMember" abstract="true" name="CommodityContractsLossesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_ForeignExchangeContractLossMember" abstract="true" name="ForeignExchangeContractLossMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="oln_IncomeStatementLocationDerivativesAxis" abstract="true" name="IncomeStatementLocationDerivativesAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oln_IncomeStatementLocationDerivativesDomain" abstract="true" name="IncomeStatementLocationDerivativesDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
</xs:schema>
