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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2019-09-20</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000041719</issuerCik>
        <issuerName>GLATFELTER P H CO</issuerName>
        <issuerTradingSymbol>GLT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001789503</rptOwnerCik>
            <rptOwnerName>Laures Wolfgang</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>96 S. GEORGE ST.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 520</rptOwnerStreet2>
            <rptOwnerCity>YORK</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>17401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>SVP, Global Supply Chain</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Laura A. Jones by POA</signatureName>
        <signatureDate>2019-09-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
