Enforcing controls on trade in dual-use items in the EU has become increasingly challenging in the past decade as the patterns of both legal and illegal trade have become more complex. Effective enforcement includes detecting and investigating breaches of the relevant legal provisions, and may require their prosecution. However, prosecution of WMD-related offences has proven challenging, as shown in a number of cases taken to court in different EU countries. This paper explains the legal and political framework for prosecutions in the area of dual-use trade controls, both internationally and in the EU and provides reflections on translating political and legal terms into effective enforcement at the regional and national levels. It also offers insights into specific prosecution cases in a number of EU countries and gives an overview of prosecution challenges derived from these and other cases. Consistency in terms of penalties is not feasible in the current EU legal setting—and may not even be desirable. Nevertheless, a number of steps could be taken to address current prosecution challenges.