Abydenus (Ancient Greek: Αβυδηνός) was a Greek historian, and the author of a History of the Chaldeans and Assyrians, of which some fragments are preserved by Eusebius in his Praeparatio Evangelica, and by Cyril of Alexandria in his work against Julian. Several other fragments are preserved by Syncellus. These were particularly valuable for chronology. An important fragment, which clears up some difficulties in Assyrian history, has been discovered in the Armenian translation of the Chronicon of Eusebius.
It is uncertain when he lived, but he is to be distinguished from Palaephatus Abydenus, who lived in the time of Alexander the Great; for this Abydenus mentions Berosus, who lived at a later period. He probably wrote around 200 BC and, as Cyril states, in the Ionic dialect.
- Smith, William (1867), "Abydenus", in Smith, William (ed.), Dictionary of Greek and Roman Biography and Mythology, 1, p. 4