Greek mythology is the body of myths and teachings that belong to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. It was a part of the religion in ancient Greece. Modern scholars refer to and study the myths in an attempt to throw light on the religious and political institutions of Ancient Greece and its civilization, and to gain understanding of the nature of myth-making itself.

The oldest known Greek literary sources, Homer's epic poems Iliad and Odyssey focus on events surrounding the aftermath of the Trojan War. Two poems by Homer's near contemporary Hesiod, the Theogony and the Works and Days, contain accounts of the genesis of the world, the succession of divine rulers, the succession of human ages, the origin of human woes, and the origin of sacrificial practices. Myths are also preserved in the Homeric Hymns, in fragments of epic poems of the Epic Cycle, in lyric poems, in the works of the tragedians of the fifth century BC, in writings of scholars and poets of the Hellenistic Age, and in texts from the time of the Roman Empire by writers such as Plutarch and Pausanias.

Archaeological findings provide a principal source of detail about Greek mythology, with gods and heroes featured prominently in the decoration of many artefacts. Geometric designs on pottery of the eighth century BC depict scenes from the Trojan cycle as well as the adventures of Heracles. In the succeeding Archaic, Classical, and Hellenistic periods, Homeric and various other mythological scenes appear, supplementing the existing literary evidence. Greek mythology has had an extensive influence on the culture, arts, and literature of Western civilization and remains part of Western heritage and language. Poets and artists from ancient times to the present have derived inspiration from Greek mythology and have discovered contemporary significance and relevance in the themes.