This chapter focuses on the emergence and development of Turkish Islamism since the transition to competitive politics in 1946 after a brief review of Islamism and secularism in the late Ottoman and early republican periods. It studies the history of Turkish Islamism in three stages: its crystallization into a distinct political party organization within right-wing milieus between 1946 and 1980; its expansion, pluralization and rise in a favorably changing domestic and international context between 1980 and 1998; and, after a setback, its hegemonic renewal at the expense of democracy and authoritarian rule by a populist leader between 1998 to the present. Thematically, the chapter addresses its durability, changing ideological characteristics, social basis, political strategies, and ideological alliances. It identifies several factors shaping the fortunes and characteristics of Turkish Islamism including its relatively secular nature and integration into the political processes, favorable modification of the parameters of state secularism in Turkey, economic transformations, and global intellectual and political trends revealing the defects of Turkish democracy and secularism.