Diadochos of Photiki was a fifth-century Christian ascetic and bishop from the province of Epirus Vetus. Born around 400, he served as the bishop of Photiki and participated in the Council of Chalcedon in 451. His theological writings, which emphasize spiritual stillness and the struggle against demonic influences, were heavily shaped by the teachings of Evagrius the Solitary and Macarius of Egypt. He is recognized as a significant figure in the development of Byzantine monasticism and the later Hesychast movement.