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

    <schemaVersion>X0607</schemaVersion>

    <documentType>3/A</documentType>

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

    <dateOfOriginalSubmission>2026-03-18</dateOfOriginalSubmission>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000912958</issuerCik>
        <issuerName>MILLICOM INTERNATIONAL CELLULAR SA</issuerName>
        <issuerTradingSymbol>TIGO</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002094821</rptOwnerCik>
            <rptOwnerName>Vanhaeren Bart Kristof</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>DORAL CONCOURSE</rptOwnerStreet1>
            <rptOwnerStreet2>8400 NW 36TH STREET, SUITE 530</rptOwnerStreet2>
            <rptOwnerCity>DORAL</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33166</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Performance Cash Award Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6944</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each Performance Cash Award Unit (&quot;PCA Unit&quot;) represents the cash equivalent of the closing price of one common share on the last trading day preceding the vesting date, plus any dividends paid on the common share, if any, since the grant date. The PCA Units were granted under the issuer's 2025 Performance Cash Award Program and reflect achievement of performance conditions at 173.41% of target. The PCA Units will vest in substantially equal installments on each of January 1, 2027 and January 1, 2028, subject to continued employment with the issuer or its subsidiaries. The PCA Units were inadvertently omitted from the reporting person's original Form 3 filing.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Bart Vanhaeren</signatureName>
        <signatureDate>2026-10-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
