The Church of Panagia Pantanassa (Ιερός Ναός Παναγίας Παντανάσσης) is one of the oldest churches in Athens, located at the heart of Monastiraki Square, near the entrance to the metro station of the same name. Dating back to the 10th–11th centuries, it is a rare example of surviving Middle Byzantine architecture in the city's busy urban core.

Originally part of a women’s monastery, from which the name "Monastiraki" (literally “little monastery”) is derived, the church was constructed as a three-aisled basilica with a dome and apses, built in traditional cloisonné masonry combining stone and brick. Over the centuries, it has undergone various renovations and additions that shaped its current appearance.

Though modest in size, the church plays an important spiritual role. It remains active and is open for worship, particularly frequented by local residents and nearby market vendors. Inside, it houses icons and later-period decorative elements. Festive liturgies are often accompanied by the unique atmosphere of the historic city center.

Today, the Church of Panagia Pantanassa is not only a place of worship but a key historical landmark — a gateway to Athens’ layered cultural landscape. Its presence on Monastiraki Square preserves the city’s Byzantine heritage and spiritual continuity amid the vibrant modern life of the capital.