In this article, Thomas Bieber analyzes the legal framework for introducing a national parcel tax on low-value consignments from third countries and identifies key constraints under WTO law, European Union law, and Austrian constitutional law. From a WTO perspective, such a measure must comply with the national treatment obligation in Article III GATT and could be justified only under the narrowly construed exceptions in Articles XIX or XX GATT. Under EU law, a parcel tax linked to importation risks being classified as a charge having equivalent effect to a customs duty under Article 28 TFEU and must also respect the prohibition of fees for ordinary customs activities under Article 52 UCC. From a constitutional perspective, while the Austrian legislature may introduce federal taxes and pursue regulatory objectives, a measure that effectively prevents imports would give rise to competence concerns given the exclusive customs competence of the EU.