St. Athanasius of Mouzaki (Greek: Άγιος Αθανάσιος του Μουζάκη; Albanian: Shën Thanasi i Muzakajve) is a Greek Orthodox church located in Kastoria, Greece.^[1][2] It was built in 1383–84 by the brothers Theodore II and Stoya of the house of Muzaka, a noble Albanian family that controlled the city at the time, and dedicated to St. Athanasius^[1][2] It is considered one of the most important monuments of 14th century Kastoria and is the last church built in Kastoria before its annexation by the Ottoman Empire.^[2]

The church is decorated with scenes of saints dressed in Byzantine clothing, a typical feature of Byzantine iconography. The frescoes are remarkable for depicting for the first time in Byzantine iconography, Jesus Christ and the Virgin Mary in imperial costume.^[3] The depiction of Virgin Mary as a queen is an atypical feature for the Byzantine iconography.^[4] Another unusual feature of the church is that, despite the fact that St. Alexander is traditionally not included among the ranks of military saints,^[5] the church of St Athanasius of Mouzaki is decorated with a portrait of St. Alexander and St. Mercurios in military clothing.

The church influenced greatly the artistic production of Kastoria and Western Macedonia in the late 14th and early 15th century.^{[6][clarification needed]}

• Principality of Muzaka