In Greek mythology, Alcyoneus or Alkyoneus (; Ancient Greek: Ἀλκυονεύς, romanized: Alkyoneús) may refer to the following characters:
Alcyoneus, one of the Gigantes and an opponent of Heracles.
Alcyoneus, son of Diomus, who was intended as a sacrifice to the monster Sybaris.
Alcyoneus, an alternate name for Ischys, the son of Elatus and Hippea, and also the lover of Coronis.
Alcyoneus, a member of the Ethiopian army who followed their leader, King Memnon, to fight on the side of the Trojans during the Trojan War.