The Holy Church of the Transfiguration of the Saviour (Ιερός Ναός Μεταμορφώσεως του Σωτήρος) is a small Byzantine church located in the historic Plaka district of Athens, at Theorias 6, on the northern slope of the Acropolis. Built in the third quarter of the 11th century, it stands as a notable example of Middle Byzantine architecture and is one of the few surviving monuments from that period in the city.
Architecturally, the church follows the cross-in-square plan without a narthex, featuring four columns supporting an octagonal "Athenian-type" dome. The masonry showcases the "cloisonné" technique—alternating stone and thin brick layers—typical of Byzantine architecture in Athens. The eastern side has three semicircular apses, and a small chapel carved into the rock on the southern side is dedicated to Saint Paraskevi of Rome.
During the Ottoman period (1456–1833), a pointed arch was added to the northern wall, reflecting Ottoman architectural influence. In the 19th century, the church underwent expansions to accommodate more worshippers, altering its original appearance.
Inside, the church features post-Byzantine frescoes from the 18th and 19th centuries, along with a marble iconostasis crafted in the 20th century. The small courtyard in front of the church houses a 17th-century marble fountain and bronze busts of former Greek President Konstantinos Tsatsos and his wife Ioanna, who lived nearby.
The church celebrates its feast day on August 6th, the Feast of the Transfiguration. It is open to visitors and, despite its modest size, offers significant interest for those passionate about history, architecture, and the spiritual heritage of Athens.