Serapion of Thmuis was a 4th-century Christian monk, scholar, and bishop in Lower Egypt. Known as the Scholastic due to his deep learning, he served as the abbot of the Monastery of Arsina and later became the bishop of Thmuis. He was a close associate of Anthony the Great, receiving one of the elder's sheepskin cloaks upon his death. Throughout his career, he acted as a key theological ally to Athanasius of Alexandria, assisting in the struggle against Arianism and representing church interests before the emperor.