Secularism in Turkey defines the relationship between religion and state in the country of Turkey. Secularism (or laicity) was first introduced with the 1928 amendment of the Constitution of 1924, which removed the provision declaring that the "Religion of the State is Islam", and with the later reforms of Atatürk, which set the administrative and political requirements to create a modern, democratic, secular state, aligned with Kemalist ideology.

Nine years after its introduction, laïcité was explicitly stated in the second article of the then Turkish constitution on February 5, 1937. The current Constitution of 1982 neither recognizes an official religion nor promotes any. This includes Islam, to which at least nominally more than 99% of its citizens subscribe.

Turkey's "laïcité" does not call for a strict separation of religion and the state, but describes the state's stance as one of "active neutrality." Turkey's actions related with religion are carefully analyzed and evaluated through the Diyanet İşleri Başkanlığı (English: Presidency of Religious Affairs). The duties of the Presidency of Religious Affairs are "to execute the works concerning the beliefs, worship, and ethics of Islam, enlighten the public about their religion, and administer the sacred worshipping places".

Turkey (Turkish: Türkiye), known officially as the Republic of Turkey ( Türkiye Cumhuriyeti (help·info)), is a Eurasian country located in Western Asia (mostly in the Anatolian peninsula) and in East Thrace in Southeastern Europe. Turkey is bordered by eight countries: Bulgaria to the northwest; Greece to the west; Georgia to the northeast; Armenia, Azerbaijan (the exclave of Nakhchivan) and Iran to the east; and Iraq and Syria to the southeast. The Mediterranean Sea and Cyprus are to the south; the Aegean Sea is to the west; and the Black Sea is to the north. The Sea of Marmara, the Bosphorus and the Dardanelles (which together form the Turkish Straits) demarcate the boundary between East Thrace and Anatolia; they also separate Europe and Asia.

Turkey is one of the six independent Turkic states. The vast majority of the population are Muslims. The country's official language is Turkish, whereas Kurdish and Zazaki languages are spoken by Kurds and Zazas, who constitute 18% of the population.