Abstract
This chapter provides an overview of trends in public opinion towards the European Union (EU). The chapter also discusses the key factors thought to explain differences in mass opinion regarding the EU. These include political economy and rationality: opinions stemming from calculations about the costs and benefits of the EU; perceptions of the national government (domestic proxies); the influence of political elites; political psychology, including cognitive mobilization (attentiveness to politics) and concerns about the loss of national identity; and, finally, the role of the mass media in driving opinions regarding the EU.