Saint Mary of the Mongols  is an Eastern Orthodox church in Istanbul. It is the only Byzantine church of Constantinople that has never been converted to a mosque, always remaining open to the Greek Orthodox Church.

Location
The church, which usually is not open to the public and lies behind a high wall, is placed in the district of Fatih, in the neighborhood of Fener. It lies on Tevkii Cafer Mektebi Sokak, at the summit of a slope overlooking the Golden Horn, and near to the imposing building of the Phanar Greek Orthodox College.