Customs law is an area of indirect tax law that is not well known outside of a small group of practitioners. It is unique in one essential respect: customs duties are a traditional own resource of the European Union that is collected by the Member States. This has given the EU institutions, and in particular the anti-fraud office of the EU (OLAF) and more recently the European Public Prosecutor Office (EPPO), the power to interpret EU customs law in autonomy, and enforce this interpretation with Member States through the working of the EU’s budget rules. It is in that context that we see today the concept of abuse of law used in novel ways, sometimes as part of criminal investigations. We review in this article the basic concepts of EU customs law and EU budget rules having an impact on how it is enforced, before reviewing the cases of the Court of Justice developing and refining the concept of abuse of law in customs and international trade law. We then question whether it is at all possible to rely on abuse of law as a basis for criminal prosecution.