The model of secularism as the overarching framework for managing the relationship between religion and politics has come under increasing scrutiny in recent International Relations (IR) scholarship, particularly in the wake of the so-called “postsecular turn”. Where once religion was thought to be an entity that was easily identifiable, definable and largely irrelevant to politics and public life, these assumptions are being increasingly brought into question. This special issue makes a specific contribution to this recent questioning of secularism within IR by noting and interrogating the multiple ways in which the boundaries between the religious and the political blur in contemporary politics. Our contributors explore the multifarious dimensions of this critical issue by asking whether the relationship between religion and politics has taken on significant new forms and dimensions in our contemporary globalised age or if we are simply beginning to recognise a pattern that has always been present. In this introduction we canvass some of the parameters of current debates on the religious and the political. We note that there are multiple and (at times) competing understandings of such key terms as religion, secularism, secularisation and the post-secular that shape and are shaped by ongoing discussions of the relationship between religion and public life. Our goal is not to close down these important points of difference through the imposition of singular understandings. We simply wish to highlight the points of contestation that continue to be significant for how we understand (or obscure) the boundaries between the religious and the political.