According to Hesiod, creation began with Chaos, an endless emptiness. From Chaos came Gaia (Earth), Tartarus (underworld), Eros (love), and Nix (night). Nix and Erebus (darkness of the underworld) produced Hemera (day) and Aether (upper sky). Gaia, without a mate, gave birth to Uranus (heaven), Orea (mountains), and Pontus (sea).

Gaia mated with her son Uranus, bearing the Titans, including Oceanus, Coeus, Crius, Hyperion, Iapetus, Theia, Rhea, Themis, Mnemosyne, Phoebe, Tethys, and Cronus. She also bore the one-eyed Cyclops and the Hecatoncheires (hundred-handed, fifty-headed giants). Uranus imprisoned these children within Gaia, causing her great pain. Gaia conspired with Cronus, who castrated Uranus, leading to the birth of the Erinyes, Giants, Meliae, and Aphrodite from Uranus's blood and semen.

Nix independently gave birth to numerous beings representing aspects of fate, destruction, death, sleep, dreams, blame, distress, and retribution. Gaia later bore additional sea deities with Pontus, including Nereus, Thaumas, Phorcys, Ceto, and Eurybia. Their offspring included Iris, the Harpies, and monstrous figures like Medusa, who was eventually slain by Perseus.

Oceanus and Tethys produced the Oceanids and all the rivers. Hyperion and Theia fathered Helios (sun), Selene (moon), and Eos (dawn). Crius and Eurybia had Astraeus, Pallas, and Perses. Astraeus and Eos produced the stars and winds. Cronus and Rhea had Hestia, Demeter, Hera, Hades, Poseidon, and Zeus.

Fearing a prophecy, Cronus swallowed each of his children. Rhea, with Gaia's help, saved Zeus by giving Cronus a stone to swallow instead. When Zeus matured, he forced Cronus to disgorge his siblings and the stone. Zeus then freed the Cyclops and Hecatoncheires, who aided him in the Titanomachy (war against the Titans), where he overthrew Cronus and imprisoned the Titans in Tartarus. Atlas was punished by holding up the sky.

After defeating the Titans, Zeus, Poseidon, and Hades divided the world. Gaia, angered by the treatment of her children, unleashed monsters like Typhon and Echidna against Zeus. Zeus married seven wives, each union producing significant deities: Metis (Athena), Themis (Hours and Fates), Eurynome (Graces), Demeter (Persephone), Mnemosyne (Muses), Leto (Apollo and Artemis), and Hera (Ares and Eileithyia). Zeus also fathered Hermes with Maia and Heracles with Alcmene. Hera, angered by Zeus's infidelity, bore Hephaestus alone.

The new rulers faced an attack from the Giants, offspring of Gaia's blood from Uranus's castration. The Giants attempted to reach Olympus by piling mountains. A prophecy stated they could only be killed with the help of a mortal. Zeus sought and harvested a protective plant before Gaia could, and with the aid of Heracles and other gods, defeated the Giants, reaffirming his rule.