Orphanotrophos (Greek: ὀρφανοτρόφος) was a Byzantine title for the curator of an orphanage (ὀρφανοτροφεῖον, orphanotropheion). The director of the most important orphanage, the imperial orphanage in Constantinople, established in the 4th century and lasting until the 13th century, eventually rose to become an office of particular significance and ranked among the senior ministers of the Byzantine state.
In the spirit of Christian philanthropy, the Byzantine world showed particular care towards the weaker members of society, including widows, orphans, the sick or the elderly. Orphans were either adopted by foster parents, or sheltered in monasteries or in orphanages, the latter often run by monasteries.
In Constantinople, the Byzantine capital, there was a particularly large orphanage in the northeastern corner of the city, at the site of the ancient acropolis of Byzantium, which eventually came under imperial patronage. According to the Patria of Constantinople, it traced its antecedents to a series of charitable establishments founded in the reign of Constantius II (ruled 337–361) by the patrikios and protovestiarios Zotikos, for which the latter was canonized by the Church. According to a novel by Emperor Leo I the Thracian in 469, Zotikos was the first to bear the title of orphanotrophos. In the 5th century, the priest Nikon and Acacius, later Patriarch of Constantinople (472–488), are known to have been successively orphanotrophoi in the capital, while another future patriarch, Euphemius (489–495) held the post in the provincial town of Neapolis.