This essay proposes definitions of key terms such as ‘minoritization’, ‘majoritization’, and ‘religious minority’, and problematizes standard criteria of identification of religious minorities while also advocating for an understanding of religious minorities as dynamic, processual, relational, contextual, situational, and intersectional. By doing this, it also warns against homogenizing representations of religious minorities and addresses minorities within minorities. It presents several important distinctions among and within religious minorities in terms of size, location, origin, legitimacy, recognition, social position, and self-perceptions. The essay discusses the mechanisms that turn assemblages of people into minorities and different criteria and strategies that establish such social formations as ‘religious minorities.’ This includes processes of recognition and non-recognition by societies and different forms of minorities (‘wild’ and ‘tame’ ones). The essay historicizes the emergence of the category and the problem of ‘religious minorities’ in the context of colonialism, modern conceptions of the nation-state, democracy, and international politics. Last but not least, it reflects on the importance of religious minorities as a theme for research, and as a lens for understanding the dynamics of religion in society.