Minors can be involved in judicial proceedings of a different Member State when they have (allegedly) committed an offence within the EU. Whereas the EU has developed instruments to facilitate cooperation between Member States in criminal matters, no specific instruments exist to deal with cross-border youth justice cases. This book assesses to what extent it is possible and feasible to develop EU cooperation in youth justice matters.In EU youth justice: The personal scope of EU criminal law and the diversity of youth justice systems, on the one hand the author examines whether youth justice matters fall within the scope of EU judicial cooperation in criminal matters. On the other hand, a thorough legal comparison is carried out between the youth justice systems of Austria, the French Community of Belgium, the Netherlands and Northern Ireland. Their similarities and differences are evaluated in terms of age limits, specialised actors (police officers, public prosecutors, courts, lawyers, support services and detention institutions), and reactions (diversion, non-custodial and custodial reactions).This book is for anyone interested in (foreign) youth justice systems, children’s rights and EU criminal law.Jantien Leenknecht obtained her Master of Laws at KU Leuven in 2017 and her PhD in 2022. From 2017 to 2022, she was active as a PhD Fellow of the Research Institute Flanders (FWO) at KU Leuven’s interdisciplinary research line Youth Law and Criminology. Her fields of interest are the age limits, relevant actors and reaction possibilities in different youth justice systems as well as the rights of the child and EU criminal procedural law.