In the last decade, the notion of sovereignty has been increasingly used in public discussions. A variety of actors areappealing to it, from systemic actors looking for ways to overcome the global governance and security crisis to sovereigntistsprotesting universalism and the weakening of the role of the state. Under these conditions, the transformationof sovereignty within integration associations is of particular interest. The concept of “strategic sovereignty” has appearedin the discourse of the most advanced among them, the European Union (EU). Among the challenges to thissovereignty, Brussels puts emphasis on the policies of China and Russia. The latter also actively appeals to the notionof sovereignty and is itself the core of another integration association—the Eurasian Economic Union (EAEU). Fromthe very creation of the Eurasian Customs Union, it has been emphasized that it borrows from the experience of theEU and aims to become a nexus in interlinking regional integration agreements across Eurasia. In the context of theconflict between Russia and the West, the EU and the EAEU are increasingly opposed to each other.This study is focused on identifying the features of the transformation of sovereignty in integration associationsbased on the example of the EU and the EAEU. The analytical focus of the evaluation of the two models is set by theconcept of four dimensions of sovereignty by S. Krasner and the phenomenon of supranationality. As the study shows,the transformation of sovereignty is not limited to the transfer of power to supranational bodies. In the EU, sovereigntyis shared among the levels of this political community, forming a multilevel system of governance. Regarding theEAEU, the literature is dominated by the opinion that the sovereignty of the participating countries is indisputable,and the association itself is purely interstate in nature. Indeed, there are practically insurmountable obstacles totransferring the issues of organization of power to other levels by the EAEU states. At the same time, different dimensionsof sovereignty here were affected by asymmetric relations with Russia even before the formation of the EAEU.The union was created on the basis and because of these dependencies, but it also transforms them.