What was the official state religion of the Ottoman Empire? The official state religion was Islam, specifically Sunni Islam for most of the empire’s history.
Islam shaped the Ottoman dynasty’s legitimacy, legal institutions, education, and public life. The sultan was a Muslim ruler and, after the Ottoman conquest of the Mamluk territories in 1517, Ottoman sultans also claimed the caliphal title. Sunni Islam was closely associated with the Hanafi school of Islamic jurisprudence.
The empire was religiously diverse. Christians, Jews, and other communities lived under Ottoman rule and were often organized through the millet system, which allowed certain religious groups to manage aspects of their internal affairs. Non-Muslim subjects generally remained legally distinct from Muslims and could be subject to taxes such as the jizya.
This diversity does not make Christianity or Judaism the state religion. Nor was Zoroastrianism the official faith. The precise answer is therefore Islam; when greater specificity is wanted, “Sunni Islam” is the historically fuller formulation.