Demophilus (Greek Δημόφιλος) was Bishop of Constantinople from 370 until 380 AD.
Demophilus was born in Thessaloniki. He served as Bishop of Beroea before being elected Bishop of Constantinople.
He was a proponent of Arianism and, as such, was removed from the throne of Saint Andrew by emperor Theodosius the Great in November of 380.
He died in Beroea in 385.