The article focuses on the concept of sovereignty – an analytical category applicable to states. However, with the emergence of new actors in the international arena, especially new types of organisations such as the European Union, the question arises: whether it is possible to apply sovereignty to entities other than states. The authors have the assumption that in the area of social sciences, it is possible to give the concept of the sovereignty a certain trait of universality, inter alia, to better reconcile the legal and political science approaches. The aim of this study is to identify and then to define an important feature of the EU, which may be sovereignty itself or its equivalent (autonomy, claim to sovereignty, quasi-sovereignty). The results of the study may lead to a better understanding of non-state subjects of public international law such as international organisations in genere, and organisations of integrational and supranational character in specie. The article is analytical, comparative and explanatory.