In Greek mythology, Licymnius (; ) was a good friend of Heracles' and an illegitimate son of Electryon, King of Tiryns and Mycenae in the Argolid (which makes him half-brother of Alcmene, mother of Heracles). His mother is given as Mideia, a Phrygian woman. One source mentions Alco (Ἀλκώ) as his sister.