In Greek mythology, Lycus, or Lykos, referred to several people.
- Lycus (brother of Nycteus) in Greek mythology, Lycus was uncle to Antiope whom Zeus impregnated. She fled in shame to King Epopeus of Sicyon and abandoned her children, Amphion and Zethuss. They were exposed on Mount Cithaeron, but were found and brought up by a shepherd. Nycteus, unable to retrieve his daughter, sent his brother Lycus to take her. He did so and gave her as a slave to his own wife, Dirce.
- Lycus a descendant of Lycus (brother of Nycteus)
- Son of Poseidon and Celaeno, brother of Eurypylus. The two brothers ruled over the Fortunate Islands.
- Son of Prometheus and Celaeno, brother of Chimaerus. The brothers are said to have had tombs in the Troad; they are otherwise unknown.
- Son of Dascylus of Mysia or Mariandyne. He was hospitable towards the Argonauts and Heracles, who conquered the land of the Bebryces (Heraclea).
- Son of Hyrieus. He became the guardian of Labdacus and Laius. He is probably the same as Lycus, brother of Nycteus.
- One of the four sons of Pandion II. Upon the death of Pandion, Lycus and his brothers (Aegeus, Nisus, and Pallas) took control of Athens from Metion, who had seized the throne from Pandion. They divided the government in four but Aegeas became king. He gave his name to the Lycians of Asia Minor, hitherto known as Milyans.