Baldwin of Hainaut (French: Baudouin de Hainaut, Latin: Balduinus de Hannonia or Haynaco) was a knight and diplomat of the Latin Empire of Constantinople. He undertook important missions to the Cumans (1240) and the Mongols (1251–52). Baldwin was originally from the County of Hainaut. The historian Charles Verlinden argues that he was the same person as Baldwin of Avesnes.