Diaspora groups are potential key players in the relation between homeland and host states and can quite tangibly affect political developments in both, as well as have an impact on various aspects of global governance (Hagel and Peretz, 2005). Theoretically this chapter focuses on the relationship between diaspora politics, transnational activism, and democratic legitimacy. Empirically, the chapter discusses the specific case of transnational activism among young Muslims in Europe. Examining the democratic credentials of diaspora groups, we explore how discourses on globalization, terror, and multicultural policies have affected the extent to which some of these groups turn to radical Islam or search for more moderate alternatives, but also how these groups are internally constituted in terms of legitimacy and accountability.