Diogenes of Cyzicus

Diogenes of Cyzicus (Ancient Greek: Διογένης ἐπίσκοπος Κυζίκου, romanized: Diogenes episkopos Kyzikou) was the metropolitan bishop of the Metropolis of Cyzicus from before 449 to after 451. He participated in the Second Council of Ephesus (449) and the Council of Chalcedon (451), where he opposed the Monophysite doctrine of Eutyches.

He is not to be confused with the 3rd century grammarian Diogenianus or Diogenes of Cyzicus, who wrote the Patria of Cyzicus and is described in the Suda.