<?xml version="1.0" encoding="UTF-8"?>
<edgarSubmission xmlns="http://www.sec.gov/edgar/npx" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>N-PX</submissionType>
    <filerInfo>
      <registrantType>IM</registrantType>
      <liveTestFlag>LIVE</liveTestFlag>
      <filer>
        <issuerCredentials>
          <cik>0001442898</cik>
          <ccc>XXXXXXXX</ccc>
          <!--Field: Pseudo-Tag; ID: Name; Data:-->
        </issuerCredentials>
      </filer>
      <flags>
        <overrideInternetFlag>false</overrideInternetFlag>
        <confirmingCopyFlag>false</confirmingCopyFlag>
      </flags>
      <periodOfReport>06/30/2026</periodOfReport>
    </filerInfo>
  </headerData>
  <formData>
    <coverPage>
      <yearOrQuarter>YEAR</yearOrQuarter>
      <reportCalendarYear>2026</reportCalendarYear>
      <reportingPerson>
        <name>MFS Investment Management CO (LUX) S.A.R.L.</name>
        <phoneNumber>617-954-5000</phoneNumber>
        <address>
          <com:street1>35, Boulevard du Prince Henri</com:street1>
          <com:city>Luxembourg</com:city>
          <com:stateOrCountry>N4</com:stateOrCountry>
          <com:zipCode>L-1724</com:zipCode>
        </address>
      </reportingPerson>
      <agentForService>
        <name>Christopher R. Bohane, Massachusetts Financial Services Company</name>
        <address>
          <com:street1>111 Huntington Ave</com:street1>
          <com:street2>21st Floor</com:street2>
          <com:city>Boston</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02199</com:zipCode>
        </address>
      </agentForService>
      <reportInfo>
        <reportType>INSTITUTIONAL MANAGER NOTICE REPORT</reportType>
        <noticeExplanation>ALL VOTES BY OTHER PERSONS</noticeExplanation>
        <confidentialTreatment>N</confidentialTreatment>
      </reportInfo>
      <fileNumber>028-13180</fileNumber>
      <leiNumber>549300YXNO4Z5XQ0O194</leiNumber>
      <otherManagersInfo>
        <otherManager>
          <icaOr13FFileNumber>028-04968</icaOr13FFileNumber>
          <crdNumber>000110045</crdNumber>
          <otherFileNumber>801-17352</otherFileNumber>
          <leiNumberOM>1G3OSH3GLGJ7X1JC5I61</leiNumberOM>
          <managerName>MASSACHUSETTS FINANCIAL SERVICES CO /MA/</managerName>
        </otherManager>
      </otherManagersInfo>
      <explanatoryInformation>
        <explanatoryChoice>N</explanatoryChoice>
      </explanatoryInformation>
    </coverPage>
    <signaturePage>
      <reportingPerson>MFS Investment Management CO (LUX) S.A.R.L.</reportingPerson>
      <txSignature>Susan Pereira</txSignature>
      <txPrintedSignature>Susan Pereira</txPrintedSignature>
      <txTitle>Authorized Person</txTitle>
      <txAsOfDate>08/26/2026</txAsOfDate>
    </signaturePage>
  </formData>
</edgarSubmission>
