In Greek mythology, Cepheus (/ˈsiːfiəs, -fjuːs/; Greek: Κηφεύς CP-hus) was the son of Aleus and Neaera or Cleobule, and brother of Amphidamas, Lycurgus of Arcadia, Auge and Alcidice. He and his brother Amphidamas are counted among the Argonauts.
Cepheus succeeded his father as the king of Tegea, Arcadia. He had twenty sons (one of whom was named Aeropus) and at least three daughters, Sterope, Aerope and Antinoe. Cepheus and his sons joined Heracles in his campaign against Hippocoon, while Sterope was given by Heracles a lock of Medusa to protect Tegea in the absence of men. According to various authors, Cepheus lost either all or seventeen of his sons, and himself was killed in that campaign.
The city of Caphyae was believed to have received its name from Cepheus.
Cepheus was said to be the founder of the town of Kyrenia in Cyprus.