Classical social scientists predicted the secularisation of modern societies, but religion has remained a stubborn presence in the social landscape, such that some scholars have talked about a “post-secular” turn. Migration has been one of the factors contributing to religious diversity in receiving societies. The continued or even growing importance of religious diversity in turn has been one of the features of the diversification of diversity. Meanwhile, faith-based associational networks play a role both in migrant integration and in maintaining transnational and diasporic links. COMPAS research on religion and migration includes work on Pentecostalism, Islam and the church.