The Western Balkans has traditionally held vital geostrategic importance for European and transatlantic security. The region has experienced great power competition for centuries and typically been referred to as the ‘powder keg of Europe.’ With the dissolution of Yugoslavia, the region witnessed serious instability and bloodshed in the form of civil wars and ethnic conflicts. Ever since the 1990s, both the European Union (EU) and the North Atlantic Treaty Organization (NATO) have played an active role in the Western Balkans, significantly contributing to the efforts to establish peace and stability. Besides playing an active role in peacekeeping and peacebuilding missions and providing economic and military aid, ever since the 2000s, the two organizations have offered a membership trajectory to the countries in the region. In fact, in 2004, Slovenia first become a NATO and then an EU member. In 2009, Albania and Croatia became members of NATO. Four years later, in 2013, Croatia became an EU member state. Finally, in 2017, Montenegro became the 29th member of NATO.