This chapter focuses on the European Union's security policy. At fist glance, EU security policy seems limited by three powerful constraints. Firstly, it is exclusively concerned with ‘soft’ security issues, such as immigration, transnational crime, and drug traffiking. Secondly, policy-making is dominated by sovereignty-conscious EU member states and national capitals. Thirdly, security is not a major driver of European integration. The chapter challenges all three of these assumptions, arguing that firstly, the EU is now involved in ‘hard’ security, especially counterterrorism but also military operations. Secondly, security policy-making is increasingly Brussels-centred. Thirdly, while European integration has been driven primarily by economic cooperation, the safeguarding of Europe's (especially internal) security has emerged as a major raison d'être of the integration project. The chapter also considers the EU's role in international security, along with its Common Security and Defence Policy and internal security.