Theodosius of Tarnovo was a 14th-century Bulgarian cleric and hermit who played a significant role in the spiritual life of the Second Bulgarian Empire. As a disciple of Gregory of Sinai, he is credited with introducing the practice of hesychasm to the region. He established the Kilifarevo monastery and school, where he served as a teacher to influential figures such as Patriarch Evtimiy. During the reign of Ivan Alexander, he worked to oppose various heresies within the church.