The Hagia Sophia (Greek: Ἁγία Σοφία, Holy Wisdom) is a church located in Thessaloniki, Greece.

Because of its outstanding Byzantine art and architecture, in addition to its importance in early Christianity, it is one of several monuments in Thessaloniki listed as a UNESCO World Heritage Site in 1988.

[2] Later in the 7th century, the present structure was erected, based on the Hagia Sophia in Constantinople (present-day Istanbul, Turkey).

[2] After the capture of Thessaloniki by the Ottoman Sultan Murad II on 29 March 1430, the church was converted into a mosque,[3] called Ayasofya Camii, keeping its old name.

Together with the Gül and the Kalenderhane Mosques in Istanbul and the destroyed Church of the Dormition in Nicaea, it represents one of the main architectural examples of this type, typical of the Byzantine middle period.