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

    <schemaVersion>X0607</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2026-03-18</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001026662</issuerCik>
        <issuerName>EURO TECH HOLDINGS CO LTD</issuerName>
        <issuerTradingSymbol>CLWT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002127693</rptOwnerCik>
            <rptOwnerName>CHEANG JANET MS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>UNIT D, 18/F., GEE CHANG HONG CENTRE</rptOwnerStreet1>
            <rptOwnerStreet2>65 WONG CHUK HANG ROAD</rptOwnerStreet2>
            <rptOwnerCity>ABERDEEN</rptOwnerCity>
            <rptOwnerNonUSStateTerritory></rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>K3</rptOwnerCountry>
            <rptOwnerZipCode>00000</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>CHEANG JANET</signatureName>
        <signatureDate>2026-04-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
