Hagia Triada ("Holy Trinity"; Greek: Ιερός Ναός Αγίας Τριάδος, romanized: Ierós Naós Agías Triádos; Turkish: Aya Triada Rum Ortodoks Kilisesi) is a Greek Orthodox church in Istanbul, Turkey.

[4] The church is located in the district of Beyoğlu, in the neighborhood of Katip Çelebi, on Meşelik sokak, near Taksim Square.

Its construction, based on the designs of the Ottoman Greek architect P. Kampanaki, began on 13 August 1876 and was completed on 14 September 1880.

[2][7][8] The Church is built in neo-baroque style with elements of a basilica,[9] and with the unusual features of twin bell towers, a large dome and a neo-Gothic facade.

[2] The Hagia Triada was the first domed Christian church that was allowed to be built in Istanbul after the Fall of Constantinople in 1453.