European integration has been an important theme for the International Relations discipline since the end of World War II, and the European Union (EU), formerly called the European Economic Community (EEC), has remained at the heart of European integration studies since then. Currently, the EU’s Western Balkans enlargement agenda presents an intriguing case for European integration studies. Although issues such as Brexit, the refugee crisis and the effects of the European debt crisis are fostering the rise of Euroscepticism, the EU maintains its enlargement perspective towards Albania, Bosnia and Herzegovina, Kosovo, Montenegro, North Macedonia, and Serbia which are known as Western Balkan states. This thesis seeks to find the main reason behind the EU’s Western Balkans enlargement agenda, and for that purpose, it presents an explanation through the security community theoretical framework. This thesis presents the analysis of the official EU documents and the discourse analysis of the statements of EU officials to provide an explanation of the integration process of the Western Balkans. It argues that the idea of expanding the European security community to the region and including the region in the common European identity is the driving force behind the EU’s enlargement agenda. The EU recognises the Western Balkan region as the missing part in the European puzzle and believes that the region’s future lies within the European community. Nonetheless, the rising Euroscepticism and the growing geopolitical rivalry between the EU and Russia function as intervening variables and affect the EU’s Western Balkans enlargement agenda in a contradictory manner.