Orestes, a Greek legendary hero, son of Agamemnon and Clytemnestra. He is represented as the avenger of his father, and the deliverer of his sister Electra, through the murder of his mother. The tragic poets enlarged and embellished the Homeric narrative. According to them, at the time of the murder of Agamemnon it was intended to despatch Orestes, but Electra saved him, and intrusted him to a slave, who carried the boy to Strophius, king in Phocis, whose wife was the sister of Agamemnon. Between Orestes and Pylades, the king's son, sprang up a friendship which has become proverbial. To avenge his father's death, the former went secretly to Argos, pretending that he brought the tidings of Orestes's death. With the complicity of Electra, he killed Clytemnestra and her paramour Aegisthus, but immediately became mad, and was pursued by the Furies until by the advice of Apollo ho took refuge with Minerva in Athens. The goddess commanded that his case should be decided by the court of the areopagus; and when they were equally divided, she pronounced him innocent. According to another legend, Apollo directed him to bring from Tauris in, Scythia to Athens the statue of Diana which had fallen from heaven.

Orestes and Pylades sailed for Tauris, and on their arrival were seized by the natives to be sacrificed to Diana. But the priestess of Diana was Iphigenia, Orestes's sister, and all three escaped with the statue of the goddess. The Furies were now appeased. Orestes ruled over his father's kingdom at Mycenae, afterward became king of Argos, and married Hermione, daughter of Menelaus. He died of the bite of a snake in Arcadia, and was buried in Sparta. The story of Orestes is the subject of dramas by Aeschylus, Sophocles, and Euripides.