Eustathius of Antioch, sometimes surnamed the Great, was a bishop and patriarch of Antioch in the 4th century.

He was a native of Side in Pamphylia. About 320 he was bishop of Beroea, and he was patriarch of Antioch before the council of Nicaea in 325. In that assembly he distinguished himself zealously against the Arians, though the Allocutio ad Imperatorem with which he has been credited is hardly genuine.

His anti-Arian polemic against Eusebius of Caesarea made him unpopular among his fellow bishops in the East, and a synod convened at Antioch in 330 passed a sentence of deposition, which was confirmed by the emperor. He was banished to Trajanopolis in Thrace, where he died, probably about 337, though possibly not until 360.

The only complete work by Eustathius is the De Engastrimytho contra Origenem (ed. by A. Jahn in Texte und Untersuchungen, ii. 4). Other fragments are enumerated by G. F. Loofs in Herzog-Hauck’s Realencyklopädie.