This chapter explores the relationship between religion and politics. It first defines the concept of religion before discussing its contemporary political and social salience in many developing countries. It then considers how religion interacts with politics and with the state in the developing world, as well as how religion is involved in democratization in the developing world by focusing on the Arab Spring and its aftermath. It also examines the differing impacts of the so-called Islamic State and Pope Francis on the relationship between religion and politics in the developing world. The chapter concludes with an analysis of the role of religion in international politics after 9/11.