In this chapter, the debates over secularism, laicism, and secularization are presented. The oppositional ideas of an “official” and an “unofficial” religion, which date back to the Ottoman Empire, are pointed out in relationship to Turkish secularism (laiklik). In its assertive nature, the latter is not a static concept; it evolved from a state “mission” associated with modernization and westernization of society to an “instrument” by which the state could make use of religion as cement to promote national unity. Within this changing environment, the Presidency of Religious Affairs (Diyanet), a state institution charged with religious affairs, evolved as well. In the last forty years, its bureaucratic structure of an agency in charge of the management of mosques and the employment of religious officers has been reshaped as the bearer of a modern interpretation of Islam. The chapter provides a concluding section devoted to the crucial role that the Diyanet has played over the past decade.