Ortakoy Mosque (Ortakoy Camii), officially the Büyük Mecidiye Camii (Grand Imperial Mosque of Sultan Abdülmecid) in Besiktas, Istanbul, Turkey, is situated at the waterside of the Ortakoy pier square, one of the most popular locations on the Bosphorus.
The original Ortakoy Mosque was built in the 18th century. The current mosque, which was erected in its place, was ordered by the Ottoman sultan Abdülmecid and built between 1854 and 1856. Its architects were Armenian father and son Garabet Amira Balyan and Nigogayos Balyan (who also designed the nearby Dolmabahce Palace), who designed it in Neo-Baroque style. Within the mosque hang several examples of Islamic calligraphy executed by the Sultan Abdülmecid himself, who was also a hattat (master calligrapher).
The wide, high windows let the ever-changing light reflections of the Bosphorus shine in the mosque.