Evagrius (d. ca 380) was bishop of Constantinople for brief periods in 370, and possibly 380.
Little was known about Evagrius. In 370, the Arians elected Demophilus to fill the bishopric vacancy after the death of Eudoxius. The Catholics and the deposed bishop of Antioch Eustathius chose Evagrius for that see; but a few months later he was banished by the emperor Valens, and remained in exile until his death.
Some sources rumoured his second election in 379 or 380 after the expelling of Demophilus by emperor Theodosius I.