The European Union (EU) is neither a state nor a traditional international organization in the classical sense. It is described as a sui generis international organization. This article first focuses on the EU’s unique structure, with a particular emphasis on the formulation of foreign policy at the EU level and the Europeanization of national foreign policy in the EU member states. In line with this perspective, the article evaluates Türkiye’s EU membership process, the Europeanization of Turkish foreign policy, and its alignment with the Common Foreign and Security Policy (CFSP) of the EU from 1999 to the present. Consequently, this article analyzes the impacts of Europeanization, de-Europeanization, and renationalization of Turkish foreign policy in the context of the EU-Türkiye relations.