This study explores Azmi Bishara’s contributions to the study of secularisation in the Arab context. It argues that Bishara’s analysis of the processes of secularisation in the West opens new horizons to approaching secularisation in Arab countries. After a close reading of the last five centuries of European history, Bishara concludes that the modern state is the basis of political and social secularisation, differentiating the religious from the mundane, and providing space for new forms of religiosity to emerge. Bishara argues that contemporary Arab and Islamic countries are not an exception to the same processes of secularisation, rejecting the widely held assumption that Islamic religiosity represents an intrinsic religious or civilizational peculiarity in adapting to the differentiation of the mundane from the religious. The specificity of these countries is historical and is related to the conditions of the modern state’s emergence and its legitimacy in the Arab context, a point Bishara emphasises in his book The Arab Question. This specificity explains the nature of contemporary patterns of Islamic religiosity, including those perpetuated by contemporary Islamic movements, as being one element of modern secularisation in Arab countries. Although ideologically resistant to secularism, these movements ultimately submit to the framework and logic of the modern state, embodying the differentiation of the mundane from the religious. Bishara’s theory proposes a re-evaluation of political Islam and sectarianism in contemporary Arab countries, treating them not as indicative of the absence of secularisation, but as two of its possible manifestations. In the end, they are a manifestation of the compound union between religion and the realms differentiated therefrom as part of modern secularisation.