When norms of Union law overlap – meaning more than one could apply – what principles determine the relationship between them? What is often supposed is that the European Court of Justice uses the principles of lex superior, lex posterior and lex specialis in situations of norm overlap, prioritizing between norms based on rank, date, and speciality. Since these principles aim to protect underlying constitutional values (such as respect for democracy, fundamental rights, and the separation of powers), there are good reasons for assuming that the ECJ does adopt this approach. However, the ECJ has not yet articulated its approach with any clarity. By presenting the results of a case study in the field of the free movement of workers, this article aims to demonstrate both the use and the utility of the principles of lex superior, lex posterior and lex specialis for resolving norm overlaps in EU law.