The literature on the development of secularism in Turkey, or laiklik, often cites the national state builders' positivist worldviews as a principal explanatory factor. Accordingly, the legal-institutional form Turkish secularism took in the 1920s and 1930s is derived, to a large extent, from the Unionists' and Republicans' science-driven, antireligious ideologies. Going beyond solely ideational narratives, this article places the making of secularism in Turkey in the context of the sociopolitical contention for national-capitalist state building. In so doing, the article contributes to the latest "spatiotemporal" turn in the secularization literature, characterized by an increased attention to historical critical junctures, and sensitivity to multiple secularities occurring in Western as well as non-Western geographies. Based on a bridging of the secularization scholarship with that of state formation, and building extensively on Turkish archival material, I argue that the trajectory, fluctuations, and contradictions of secularization can be closely associated with two intertwined master processes: (1) the construction of internal and external sovereign state capacity, and (2) geographically specific trajectories of class formation/dynamics. The Turkish case demonstrates that secular settlements cannot be explained away simply by reference to the guiding ideas of actors. Contentious episodes such as civil-bureaucratic conflict, war and geopolitics, and class struggles/alliances make a significant imprint on the secularizing process.