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

    <schemaVersion>X0202</schemaVersion>

    <documentType>3/A</documentType>

    <periodOfReport>2006-01-09</periodOfReport>

    <dateOfOriginalSubmission>2006-01-11</dateOfOriginalSubmission>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001043604</issuerCik>
        <issuerName>JUNIPER NETWORKS INC</issuerName>
        <issuerTradingSymbol>JNPR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001349430</rptOwnerCik>
            <rptOwnerName>Minshull Edward</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1194 NORTH MATHILDA AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SUNNYVALE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94089</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP Worldwide Field Operations</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>By: Mitchell L. Gaynor, Attorney-in-Fact  For: Edward Minshull</signatureName>
        <signatureDate>2006-01-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
