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 became patriarch of Antioch shortly 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. The Commentary on the Hexameron attributed to him in the manuscripts is not authentic.