Religion in Istanbul

Religion in Istanbul covers the issue of religion in the city of Istanbul, Turkey. More than 90% of Istanbul's population are Sunni Muslims and Alevism forms the second biggest religious group. A 2019 survey study by KONDA that examined the religiosity of the voting-age adults in Istanbul showed that 47% of the surveyed had a religion and were trying to practise its requirements. This was followed by nonobservant people with 34% who identified with a religion but generally did not practise its requirements. 11% stated they were fully devoted to their religion, meanwhile 4% were non-believers who did not believe the rules and requirements of a religion and 4% were atheists who did not believe in religion at all. 24% of the surveyed also identified themselves as "religious conservatives".

According to the 2000 census, there were 2691 active mosques, 123 active churches and 20 active synagogues in Istanbul; as well as 109 Muslim cemeteries and 57 non-Muslim cemeteries. Religious minorities include Greek Orthodox Christians, Armenian Christians, Catholic Levantines, Assyrian Christians, and Sephardic Jews. Some neighbourhoods have been known with their sizeable populations of these ethnic groups, such as the Kumkapı neighbourhood, which had a significant Armenian population, the Balat neighbourhood, which used to have a sizeable Jewish population, the Fener neighbourhood with a large Greek population, and some neighbourhoods in Nişantaşı and Pera, which had sizeable Levantine populations. In some quarters, such as Ortaköy or Kuzguncuk, an Armenian church sits next to a synagogue, and on the other side of the road a Greek Orthodox church is found beside a mosque.