Michael IX Palaiologos or Palaeologus (Greek: Μιχαήλ Θ΄ Παλαιολόγος, Mikhaēl IX Palaiologos), (17 April 1277 – 12 October 1320, Thessalonica, Greece), reigns as Byzantine co-emperor with full imperial style 1294/1295–1320.

Michael IX is the eldest son of Andronikos II Palaiologos and Anna of Hungary (1260-1281), daughter of Stephen V of Hungary.