Amphion ("native of two lands") and Zethus, in ancient Greek mythology, were the twin sons of Zeus by Antiope. When children, they were exposed on Mount Cithaeron , but were found and brought up by a shepherd. Their mother had abandoned them when she fled in shame because of her pregnancy by a man other than her husband (who was either King Nycteus of Thebes or the river god Asopus). She married Epopeus, King of Sicyon. Nycteus, unable to retrieve his wife, sent his brother Lycus to take her. He did so and gave her as a slave to his own wife, Dirce.

Amphion became a great singer and musician after Hermes taught him to play and gave him a golden lyre, Zethus a hunter and herdsman. They punished King Lycus and Queen Dirce for cruel treatment of Antiope, their mother, whom was treated as a slave. Dirce was tied to the horns of a bull as revenge. They built and fortified Thebes, huge blocks of stone forming themselves into walls at the sound of Amphion's lyre. Amphion married Niobe, and killed himself after the loss of his wife and children at the hands of Apollo and Artemis (see Niobe). Zethus married Aedon, or sometimes Thebe. The brothers were buried in one grave.

Compare with Castor and Polydeuces (the Dioscuri) of Greece, and with Romulus and Remus of Rome.

Alternative: Zethos