<?xml version="1.0" encoding="UTF-8"?>
<edgarSubmission xmlns="http://www.sec.gov/edgar/thirteenffiler" xmlns:com="http://www.sec.gov/edgar/common">
  <schemaVersion>X0202</schemaVersion>
  <headerData>
    <submissionType>13F-NT</submissionType>
    <filerInfo>
      <liveTestFlag>LIVE</liveTestFlag>
      <flags>
        <confirmingCopyFlag>false</confirmingCopyFlag>
        <returnCopyFlag>false</returnCopyFlag>
        <overrideInternetFlag>false</overrideInternetFlag>
      </flags>
      <filer>
        <credentials>
          <cik>0000796370</cik>
          <ccc>XXXXXXXX</ccc>
        </credentials>
      </filer>
      <periodOfReport>03-31-2026</periodOfReport>
    </filerInfo>
  </headerData>
  <formData>
    <coverPage>
      <reportCalendarOrQuarter>03-31-2026</reportCalendarOrQuarter>
      <filingManager>
        <name>Acadian Inc</name>
        <address>
          <com:street1>200 STATE ST., SUITE 601A</com:street1>
          <com:city>BOSTON</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02109</com:zipCode>
        </address>
      </filingManager>
      <reportType>13F NOTICE</reportType>
      <form13FFileNumber>028-11931</form13FFileNumber>
      <otherManagersInfo>
        <otherManager>
          <cik>0000916542</cik>
          <form13FFileNumber>028-05990</form13FFileNumber>
          <name>ACADIAN ASSET MANAGEMENT LLC</name>
        </otherManager>
      </otherManagersInfo>
      <provideInfoForInstruction5>Y</provideInfoForInstruction5>
      <additionalInformation>Acadian Inc. ("Acadian") is the operating U.S. holding company of certain asset management subsidiaries of Acadian Asset Management Inc  that are subject to applicable 13F filing requirements. Acadian expressly disclaims beneficial ownership of all reported securities. Acadian does not exercise voting or investment power over any reported security. Each Acadian asset management firm exercises such power independently of Acadian and one another.</additionalInformation>
    </coverPage>
    <signatureBlock>
      <name>Patrick Golden</name>
      <title>Investment Operations and Compliance Manager</title>
      <phone>617-259-0015</phone>
      <signature>Patrick Golden</signature>
      <city>Holbrook</city>
      <stateOrCountry>MA</stateOrCountry>
      <signatureDate>04-01-2026</signatureDate>
    </signatureBlock>
  </formData>
</edgarSubmission>
