The idea of an “Islamic civilization” emerged in the very late period of the Ottoman Empire in the context of complex and multi-dimensional modernization and secularization processes. Enunciated by the Young Ottomans in the 1870s and gaining prominence in the time of Sultan Abdülhamid II, Islamic civilization was conceived, at least in part, as a counter-point to European and other civilizations. Although both its proponents and opponents assume that the religion of Islam lies at its heart, the paper will show that the idea of an Islamic civilization is a secular idea or, more precisely, one that bears the imprint of secularization. Using the work of Wilfred Cantwell Smith, among others, the argument will draw on a conception of religion as a reified category which entails that, as such, religion is conducive to secularization. It will build on and extend on this conception of religion by proposing that Islamic civilization, also a reified concept, is a further step in the direction of secularization. The paper will show this by analyzing Turkish Islamic thought, focusing particularly on Necip Fazıl Kısakürek, an Islamic thinker of the early Republican era, and the more recent figure of Ahmet Davutoğlu. The material presented here will challenge the conventional understanding of “religion” and “secularity” by highlighting that the boundaries between the two are constantly shifting and evolving.