This article asks rather surprisingly is there a place for religion and spirituality in a critical theory of international relations (IR)? The usual answer is ‘no’ because of critical theory’s generally negative assessment of religion in domestic and international politics. However, while many of these criticisms can be acknowledged, a critical theory of IR still has to grapple with the more complex understanding of religion that already exists within critical theory, and with the global resurgence of religion in international relations. It also has to grapple, with ‘the rise of the rest’ (the global South), with how Eurocentric its concept of religion actually is, and how rooted it is in the European experience of modernisation. However, for the people of the global South – which comprises most of the people in the world – the struggle to ‘live faithfully’ amid the problems of world poverty, climate change, conflict and development can not be separated from their struggle for justice and emancipation. Therefore, a greater dialogue between critical theory, theology, and the study of international relations is necessary if critical theory is to more fully and creatively contribute to our understanding of some of the most important issues in international politics in the 21st century.