Karakalou Monastery, Orthodox monastery on Mount Athos, Greece

Karakalou Monastery is an Orthodox monastery on the southeastern slope of Mount Athos in Greece, sitting at around 200 meters above sea level. The complex is built in stone and groups together a church, living quarters, several outbuildings, and defensive towers arranged across rocky ground.

The monastery was founded in the first half of the 11th century but fell into disrepair during the 13th century after pirate raids in the region. It was later revived thanks to the support of Moldavian rulers, who funded its restoration and helped repopulate it.

The monastery is named after the monk Nicholas Karakallas, who is thought to have founded it around the late 10th or early 11th century. Its katholikon, dedicated to Saints Peter and Paul, holds frescoes and icons painted by Dionysius of Fourna in the 18th century. Two of its monks are venerated as saints: Gervasios the Fool for Christ, who died in the early 18th century, and the new martyr Gideon, slaughtered at Tyrnavos on 30 December 1818.

Access is open only to men who hold a special permit called a diamonitirion, as the Mount Athos peninsula enforces strict entry rules. The number of visitors allowed each day is limited, so it is worth applying for the permit well in advance.

The monastery's best-known monk is Gervasios the Fool for Christ, who lived as a ragged ascetic around the walls and died in the early 18th century. Its second saint, Gedeon, was a monk here for 35 years before the Turks beheaded him at Tyrnavos on 30 December 1818; he is that town's patron saint.