In Greek mythology, Phylacus (/ˈfɪləkəs/; Ancient Greek: Φύλακος means "guardian"^[1]) was the name of the following figures:

• Phylacus, founder of the city of Phylace, Thessaly.^[2] He was the son of Deioneus and Diomede, husband of Clymene^[3] (Periclymene), and the father of Iphiclus,^[4] Alcimede,^[5] Evadne^[6] and possibly Clymenus.^[7] In some accounts, Phylacus was also called the father of Alcimache who became the mother of Ajax the Lesser to Oileus.^[8] His children and grandchildren are sometimes referred to by the patronymic Phylacides.^[9] His grandson through Iphiclus was also named Phylacus.^[2] In some accounts, his grandsons Protesilaus and Podarces were called his sons by Astyoche.^[10]
• Phylacus, a Trojan who was killed by Leitus.^[11]
• Phylacus, a hero who had a sanctuary in Delphi. He was one of the four heroes whose ghosts terrified the Gaulish troops that attacked Delphi.^[12]