Alexios III of Trebizond (d. 1390)
Alexios III Megas Komnenos (Greek: Αλέξιος Μέγας Κομνηνός, 5 October 1338 – 20 March 1390), or Alexius III, was Emperor of Trebizond from December 1349 until his death. He is perhaps the best-documented ruler of that country, and his reign is distinguished by a number of religious grants and literary creations.

He was the son of Emperor Basil of Trebizond and his second (and bigamous) wife, Irene of Trebizond. Alexios III was originally named John (Ιωάννης, Iōannēs), and took the name Alexios either in memory of his older brother who had died prematurely or of his paternal grandfather, Emperor Alexios II of Trebizond.

His personal appearance was described by George Finlay as "extremely noble". Finlay contributes the following details: "He was florid, blonde, and regular-featured, with an aquiline nose, which, his flatterers often reminded him, was considered by Plato to be a royal feature. In person he was stout and well formed; in disposition he was gay and liberal; but his enemies reproached him with rashness, violence, and brutal passions."