Theodora Komnene Kantakouzene (Greek: Θεοδώρα Κομνηνή Καντακουζηνή;[a] c. 1340 – after 1390) was Empress of the Empire of Trebizond as the consort of Emperor Alexios III Megas Komnenos from their marriage in 1351 until her retirement after her husband's death in 1390.

Donald Nicol presumes that the Byzantine Emperor John VI directed the search, "for the wife found was his cousin's daughter.

Her new husband was about a week short of his thirteenth birthday; Theodora is considered likely to have been of an equivalent age.

[4] Panaretos' only notice of Theodora which can not be explained as part of her role as wife or Empress is her surprising participation in the funeral procession for the illegitimate son of Alexios, Andronikos, along with her rival, his mother; Andronikos had died under suspicious circumstances after falling from the citadel 14 March 1376.

A portrait of Theodora and Alexios was painted on a wall of the Panagia Khrysokephalos Church in Trebizond, but was destroyed sometime after C. Texier made a drawing of it in the 1860s.