Clytemnestra, in Greek mythology, was the wife of Agamemnon, and the half-sister of Helen of Troy.
In Aeschylus' Oresteia, she murders Agamemnon – said by Euripides to be her second husband – and the Trojan princess Cassandra, whom Agamemnon had taken as a war prize following the sack of Troy; however, in Homer's Odyssey, her role in Agamemnon's death is unclear and her character is significantly more subdued.