Since the nineteenth century, social theorists of religion have claimed that the rise of modernity is synonymous with the decline of religion and the spread of secularism. Since the 1960s, critics have contended that modernization is compatible with faith and that the contemporary resurgence of religion marks the desecularization of the world. While modernity is predominantly secular, it seems that late modernity has a significant religious dimension. However, the modern is not simply an exit from religion or theology but in large measure the product of shifts in theological discourse and changes within religious traditions. So given its origins, there is no single modernity but rather alternative, rival modernities (both Western and non-Western) that are variously more secular or more religious. Secularism, it turns out, is primarily a modern, Western ideal that abstracts from the reality of communities and countries. This chapter will discuss the work of social theorists of religion such as Peter Berger, David Martin, and Grace Davie on the dynamics of secularism in the contemporary world. It will also draw on philosophers, theologians, and anthropologists – including Charles Taylor, John Milbank, and Talal Asad – to highlight the limits of secularism and the potential for intercultural dialogue between religious traditions. The focus will be on Jews, Christians, and Muslims in Europe. Secularism as a concept has a long history stretching back to the late Middle Ages, but the chapter will mostly analyze the last century. The chapter will combine conceptual ideas with some political analysis and ideas for policymaking in the specific domain of intercultural and interreligious dialogue.