In Greek mythology, Amphiaraus (or Amphiaraos, "doubly cursed" or "twice Ares-like") was the son of Oecles and Hypermnestra, and husband of Eriphyle. Amphiaraus was the King of Argos along with Adrastus— the brother of Amphiaraus' wife, Eriphyle— and Iphis. Amphiaraus was a seer, and greatly honored in his time. Both Zeus and Apollo favored him, and Zeus gave him his oracular talent. In the generation before the Trojan War, Amphiaraos was one of the heroes present at the Calydonian Boar Hunt.

The material of the tragic war of the Seven Against Thebes was taken up from several points-of-view by each of the three great Greek tragic poets. Eriphyle persuaded Amphiaraus to take part in the raiding venture, against his better judgment, for he knew he would die. She had been persuaded by Polynices, who offered her the necklace of Harmonia, daughter of Aphrodite, once part of the bride-price of Cadmus, as a bribe for her advocacy. Amphiaraus reluctantly agreed to join the doomed undertaking, but aware of his wife's corruption, asked his sons, Alcmaeon and Amphilochus to avenge his inevitably coming death by killing her, should he not return. On the way to the battle, Amphiaraus repeatedly warned the other warriors that the expedition would fail, and blamed Tydeus for starting it. He would eventually prevent Tydeus from being immortalized by Athena because of this. Despite this, he was possibly the greatest leader in the attack. During the battle, Amphiaraus killed Melanippus. In the battle, Amphiaraus sought to flee from Periclymenus, the "very famous" son of Poseidon, who wanted to kill him, but Zeus threw his thunderbolt, and the earth opened to swallow Amphiaraus together with his chariot. Thus chthonic hero Amphiaraus was propitiated and consulted at his sanctuary.