The Bulgarian St. Stephen Church, also known as the Bulgarian Iron Church, is a Bulgarian Orthodox church in Balat, Istanbul, Turkey. It is famous for being made of prefabricated cast iron elements in the Neo-Byzantine style. The church belongs to the Bulgarian Christian minority in the city.

Balat is a neighbourhood in the municipality and district of Fatih, Istanbul Province, Turkey. Its population is 11,656 (2022). It is in the old city on the European side of Istanbul, on the western shore of the Golden Horn, sandwiched between Fener and Ayvansaray. Historically, it was the center of the Jewish community in Istanbul.