Since the 1990s, the European Union began to develop a process of expansion throughout the rest of Europe, which is still actively carried out today. In this sense, one of the focuses of the EU enlargement policy was, and still is, the Balkan region and, in particular, Kosovo, a territory of acute conflicts for ethno-religious reasons. Consequently, this paper aims to analyze the implementation of the European Union's enlargement policy in the Balkan region and, specifically, in Kosovo. Therefore, it will be approached from its origin to its deployment in Southeastern Europe, in order to then demonstrate the implementation of the different mechanisms that sustain this policy, based on the case study of Kosovo. The enlargement policy in the Balkan region is one of the most effective instruments of the European Union's political action. It responds to the strategic interests of the organization in terms of stability, security and conflict prevention.