In Greek mythology and later Roman mythology, the Cyclopes are giant one-eyed creatures. Three groups of Cyclopes can be distinguished. In Hesiod's Theogony, the Cyclopes are the three brothers Brontes, Steropes, and Arges, who made for Zeus his weapon the thunderbolt. In Homer's Odyssey, they are an uncivilized group of shepherds, the brethren of Polyphemus encountered by Odysseus. Cyclopes were also famous as the builders of the Cyclopean walls of Mycenae and Tiryns.

Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories concern the ancient Greek religion's view of the origin and nature of the world; the lives and activities of deities, heroes, and mythological creatures; and the origins and significance of the ancient Greeks' cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of ancient Greece, and to better understand the nature of myth-making itself.