The Monastery of Saint John the Theologian is a Greek Orthodox monastery founded in 1088 in Chora on the island of Patmos. It is named after St. John of Patmos, the author of the Christian Book of Revelation who, according to the text, lived on the island when visions of the apocalypse came to him. Since its founding, the monastery has been a pilgrimage site and a place of Greek Orthodox learning and worship. The monastery is unique in that it integrated from its founding the surrounding community of Chora, which was built around its fortifications. Religious ceremonies that date back to the early Christian period are still practiced within the monastery today. Because of its sacred significance, uninterrupted architectural evolution, and the exceptional preservation of early Christian customs, the monastery was declared a UNESCO World Heritage Site in 1999, along with the town of Chora and the nearby Cave of the Apocalypse.

Patmos is a Greek island in the Aegean Sea. It is famous as the location where John of Patmos received the visions found in the Book of Revelation of the New Testament, and where the book was written.