This chapter outlines a conceptual framework for understanding the role of the European Union (EU) as an international actor. This analytical model rests on three 'legs' - interests, institutions and identities. A constant theme throughout has been the limitations of the dominant neo-realist approach to foreign policy analysis, and the need to consider both the material and ideational factors defining Europe's Common Foreign and Security Policy (CFSP). Attention has been drawn both to the role of institutional politics in shaping policy outcomes, and to the importance of culture and identity to foreign policy behaviour. The chapter provides an overview and analysis of some of the non-realist approaches to international relations and foreign policy, and proposes an analytical framework with which to explore the complex interplay of factors affecting European foreign policy. This framework is based on a synthesis of elements of social constructivism, the new institutionalism and neo-classical realism.