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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2026-01-05</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000051434</issuerCik>
        <issuerName>INTERNATIONAL PAPER CO /NEW/</issuerName>
        <issuerTradingSymbol>IP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001842788</rptOwnerCik>
            <rptOwnerName>Flores Melissa S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O INTERNATIONAL PAPER COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>6400 POPLAR AVENUE</rptOwnerStreet2>
            <rptOwnerCity>MEMPHIS</rptOwnerCity>
            <rptOwnerState>TN</rptOwnerState>
            <rptOwnerZipCode>38197</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>SVP &amp; CHRO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <remarks>Power of Attorney on file.</remarks>

    <ownerSignature>
        <signatureName>/s/ Vincent T. Smith, attorney-in-fact for Ms. Flores</signatureName>
        <signatureDate>2026-01-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
