Acacius of Melitene was a 5th-century metropolitan bishop who served the Christian community in Eastern Anatolia. During the Council of Ephesus in 431, he acted as a significant supporter of Cyril of Alexandria. He stood in opposition to Nestorius, participating in the theological debates of the era by delivering a homily and exchanging correspondence with Cyril. His leadership in Melitene preceded the tenure of his successor, Constantine.