The EU’s foreign policy commitment to contribute to the development of international law, now codified in article 3(5) TEU, is one fraught with ambiguity, both in terms of its legal content and its operationalization. Unlike most foreign policy objectives included in the EU treaties, the EU’s aspiration to develop international law is not only a singular to the constitutive instrument of an international organisation, it is also amiss from the foreign policy constitutions of the majority of its member states. The European Court of Justice’s case law, in turn, offers little guidance as to its content.