The principle of equal authenticity of the different official language versions has been codified in European Union (EU) law. This article discusses aspects of neology creation that can be observed in equally authentic texts written in the 24 official languages of the EU. Translators working in collaboration with legal specialists and drafters in a complex process of controlled text production within the European institutions play a key role in coining Euro-terminology in the text versions of their first language. These neologisms were in most cases first expressed in Euro-English, the main procedural language. In accordance with Fisher (2010), Temmerman suggests considering Euro-neologisms in 24 Euro-languages as examples of “multilingual primary term creation”, and points out some of the complexities involved. The heritage of several legal cultures and their discursive traditions appear to have an impact on EU terminological neologisms. The relative impact of the transposition of European directives and their neologisms on existing terminology in national law is shown by comparing Euro-Dutch terminology in a directive on migration to terminology in Dutch legal documents and in legal documents in Dutch in Belgium after adopting the national provisions that are necessary to comply with the directive. In this case study the impact of Euro-Dutch on legal Dutch in the Netherlands and in Belgium appears to be minimal.