The Czech Republic’s EU policy and its positions on specific EU issues are influenced by both external and internal factors. The role of external factors (i.e. the actions of other member states, EU-level decisions, and international developments) is examined throughout this book when it comes to specific issues and policies. In this chapter, the domestic sources of Czech European policy are examined more closely. These include national identity and public opinion, and the views of political parties and elites. Interest groups also exert influence on Czech EU policy; however, their role will be examined in subsequent chapters dealing with the specific policies on which they are active.