<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0708</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001528491</cik>
        <entityName>Thetis Pharmaceuticals LLC</entityName>
        <issuerAddress>
            <street1>80 Meadows Road</street1>
            <city>Deep River</city>
            <stateOrCountry>CT</stateOrCountry>
            <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
            <zipCode>06417</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>203-470-7772</issuerPhoneNumber>
        <jurisdictionOfInc>CONNECTICUT</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Limited Liability Company</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Gary</firstName>
                <lastName>Mathias</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Thetis Pharmaceuticals LLC</street1>
                <street2>80 Meadows Rd</street2>
                <city>Deep River</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>06417</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Manager</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Walter</firstName>
                <lastName>Ogier</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>9932 Cottage Lane</street1>
                <city>Union Pier</city>
                <stateOrCountry>MI</stateOrCountry>
                <stateOrCountryDescription>MICHIGAN</stateOrCountryDescription>
                <zipCode>49129</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Manager</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Frank</firstName>
                <middleName>C.</middleName>
                <lastName>Sciavolino</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>15 Applewood Drive</street1>
                <city>Quaker Hill</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>06375</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Manager</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Dennis</firstName>
                <lastName>Willson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>P.O. Box 5000, PMB 512</street1>
                <city>Rancho Sante Fe</city>
                <stateOrCountry>CA</stateOrCountry>
                <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                <zipCode>92067</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Manager</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Fabio</firstName>
                <lastName>Cataldi</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Thetis Pharmaceuticals LLC</street1>
                <street2>80 Meadows Rd</street2>
                <city>Deep River</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>06417</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Manager</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>David</firstName>
                <lastName>Cook</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Thetis Pharmaceuticals LLC</street1>
                <street2>80 Meadows Rd</street2>
                <city>Deep River</city>
                <stateOrCountry>CT</stateOrCountry>
                <stateOrCountryDescription>CONNECTICUT</stateOrCountryDescription>
                <zipCode>06417</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Manager</relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pharmaceuticals</industryGroupType>
        </industryGroup>
        <issuerSize>
            <revenueRange>Decline to Disclose</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06b</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>false</isAmendment>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2026-08-13</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>false</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isDebtType>true</isDebtType>
            <isOptionToAcquireType>true</isOptionToAcquireType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>1000000</totalOfferingAmount>
            <totalAmountSold>560300</totalAmountSold>
            <totalRemaining>439700</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>10</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>Thetis Pharmaceuticals LLC</issuerName>
                <signatureName>Gary Mathias</signatureName>
                <nameOfSigner>Gary Mathias</nameOfSigner>
                <signatureTitle>Chief Executive Officer</signatureTitle>
                <signatureDate>2026-10-13</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
