Michael IV Autoreianos (Greek: Μιχαὴλ Αὐτωρειανός; died 26 August 1212) was the Patriarch of Constantinople from 1208^[1] to his death in 1212.

Michael was a well-educated man and a member of the literary circle around Eustathius of Thessalonica. In the ecclesiastic hierarchy, he had reached the post of megas sakellarios at the time of the sack of Constantinople by the Fourth Crusade in 1204.^[2] According to a letter written by John Apokaukos in 1222, he was nominated bishop of Amastris, but David Komnenos rejected his nomination as an infringement of his sovereignty.^[3] In 1208 he was made patriarch by Theodore I Laskaris, in succession of John X who had died in 1206. Laskaris had established a Byzantine Greek successor state in Asia, the Empire of Nicaea, and had tried to persuade John X to join him, but he had refused because of old age and died shortly after.^[4]

Shortly after his appointment, on 20 March 1208, Michael IV performed Theodore Laskaris' coronation as emperor (Laskaris had already been acclaimed emperor in 1205). He also took the highly unusual move, contrary to both Byzantine tradition and Orthodox doctrine, of promising remission of sins for Laskaris' soldiers who fell in battle. It appears however that this pledge was of short duration. He died at Nicaea on 26 August 1212.^[5]