In Greek mythology and later Roman mythology, the Cyclopes (/saɪˈkloʊpiːz/ sy-KLOH-peez; Greek: Κύκλωπες, Kýklōpes, "Circle-eyes" or "Round-eyes";^[1] singular Cyclops /ˈsaɪklɒps/ SY-klops; Κύκλωψ, Kýklōps) are giant one-eyed creatures.^[2] Three kinds of Cyclopes can be distinguished. In Hesiod's Theogony, the Cyclopes are three brothers—Brontes, Steropes, and Arges—who create Zeus's thunderbolt, Poseidon's trident, and Hades' Helm of Darkness. The Cyclopes of Homer's Odyssey are a group of uncivilized, cave-dwelling shepherds, including Polyphemus, whom Odysseus encounters. A third group of Cyclopes reputedly constructed the Cyclopean walls of Mycenae and Tiryns.

In Cyclops, the fifth-century BC play by Euripides, a chorus of satyrs offers comic relief based on the encounter of Odysseus and Polyphemus. The third-century BC poet Callimachus makes the Hesiodic Cyclopes the assistants of smith-god Hephaestus, as does Virgil in the Latin epic Aeneid, where he seems to equate the Hesiodic and Homeric Cyclopes. From at least the fifth century BC, Cyclopes have been associated with the island of Sicily and the volcanic Aeolian Islands.