Citizenship education has been the subject of growing attention in policy and academic circles over the past 20 years. Citizenship education curricula have typically focused on national institutions, issues, and ties. Citizenship education has been closely bound up with the legitimacy of the nation-state, and alternative institutions and citizenships thus present a significant challenge not only to the contents of national curricula, but also to the traditional purpose and assumptions of citizenship education. The articles in this special issue seek to explore how nation-states have responded to this challenge by exploring, from a comparative perspective, the ways in which one supra-national, regional citizenship (namely European citizenship) has been defined in the citizenship education curricula of states from across Europe. This Introduction describes the supra-national policy developments that have led European states to consider reforming their citizenship education curricula. (Contains 2 tables and 8 notes.)