Pegasus (Ancient Greek: Πήγασος, Pḗgasos; Latin: Pegasus, Pegasos) is one of the best known creatures in Greek mythology. He is a winged divine stallion also known as a horse usually depicted as pure white in color. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. He was the brother of Chrysaor, born at a single birthing when his mother was decapitated by Perseus. Greco-Roman poets write about his ascent to heaven after his birth and his obeisance to Zeus, king of the gods, who instructed him to bring lightning and thunder from Olympus. Friend of the Muses, Pegasus is the creator of Hippocrene, the fountain on Mt. Helicon. He was captured by the Greek hero Bellerophon near the fountain Peirene with the help of Athena and Poseidon. Pegasus allows the hero to ride him to defeat a monster, the Chimera, before realizing many other exploits. His rider, however, falls off his back trying to reach Mount Olympus. Zeus transformed him into the constellation Pegasus and placed him up in the sky.

Hypotheses have been proposed regarding its relationship with the Muses, the gods Athena, Poseidon, Zeus, Apollo, and the hero Perseus.

The symbolism of Pegasus varies with time. Symbol of wisdom and especially of fame from the Middle Ages until the Renaissance, he became one symbol of the poetry and the creator of sources in which the poets come to draw inspiration, particularly in the 19th century. Pegasus is the subject of a very rich iconography, especially through the ancient Greek pottery and paintings and sculptures of the Renaissance.