The Koutloumousiou Monastery (Greek: Μονή Κουτλουμουσίου) or Koutloumousi (Κουτλουμούσι) is an Eastern Orthodox monastery in the monastic state of Mount Athos in Greece.

Its was founded in the 11th century by Kallistos Koutloumous, an orthodox monk from the city of Iconium in Minor Asia.

The first benefactor was the byzantine Emperor Alexios I Komnenos, who appreciated the piety of Kallistos and strengthened the Monastery.

[1] The monastery was raised with the help of voivodes Nicolae Alexandru Basarab and Vladislav Vlaicu from Wallachia, while other Wallachian voivodes contributed with substantial financial donations (Mircea cel Bătrân, Laiotă Basarab, Basarab cel Tânăr, Vlad al IV-lea Călugărul, Vlad al VI-lea Înecatul, Vlad al VII-lea Vintilă, Radu cel Mare, Neagoe Basarab).

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