This Article deals with the issues related to the judicial review of transnational acts which are adopted particularly within the context of the European integration process. The European Union is a privileged playground for the development of administrative acts of this type, primarily because of the existence of various and diverse administrative cooperation mechanisms. Transnational administrative acts are, either because of their adoption process or because of their conditions of enforcement, governed by at least two national legal orders. The question of the availability of judicial review in the context of transnational administrative acts is a complex one, because the presence of one exogeneous element may disrupt the straightforward path toward the right of access to courts—as both the determination of the competent court and the scope of the review carried out by the court seized become uncertain. This Article first draws up a typology of transnational administrative acts. Second, on the basis of this typology, this Article analyzes the solutions developed by the case law of the Court of Justice and assesses them in the light of the principles of territoriality of administrative law and the right to effective judicial protection.