In Greek mythology, Alcmaeon, or Alkmáon, was the son of Amphiaraus and Eriphyle. Eriphyle persuaded Amphiaraus to take part in the Seven Against Thebes raid, though he knew he would die. Eriphyle was convinced to support the battle by Polynices, who offered her the necklace of Harmonia.

Amphiaraus asked his sons, Alcmaeon and Amphilochus, to avenge his death, and Alcmaeon killed his mother when Amphiaraus died. He was pursued by the Erinyes as he fled across Greece, eventually landing the court of King Phegeus, who gave him his daughter, Alphesiboea, in marriage. Exhausted, Alcmaeon asked an oracle how to avoid the Erinyes and was told that he needed to stop where the sun was not shining when he killed his mother. That was the mouth of the river Achelous which had been silted up. The god of that river, also named Achelous, gave him his daughter, Callirhoe in marriage if Alcmaeon would retrieve the necklace and clothes which Eriphyle wore when she persuaded Amphiaraus to take part in the battle. Alcmaeon had given these jewels to Phegeus who had his sons kill Alcmaeon when he discovered Alcmaeon's plan.

In an alternate version, he took part in the battle of the Epigonoi where he was killed by Laodamas.

Acarnan was Alcmaeon's son.

Alcmaeon accidentally left his children, Tisiphone and Amphilochus, with Creon in Corinth. Creon's wife sold Tisiphone into slavery, envious of her beauty. She didn't realize that Tisiphone's purchaser was acting on behalf of her father. When Alcmaeon returned, he rescued his daughter and recovered his son.