珀伽索斯（古希腊语：Πήγασος, Pégasos, Latin Pegasus），又称佩格索斯，俗称天马或飞马，是希腊神话中最著名的奇幻生物之一。他是一只长有双翼的马，通常为白色。他是美杜莎与海神波塞冬所生，角色是马神。他的母亲美杜莎被珀耳修斯割下头颅时，他和兄弟巨人克律萨俄耳一起出生。希腊罗马诗人描写他出生后升天拜见众神之王宙斯，宙斯指示他从奥林巴斯带来闪电和雷声。他是缪斯女神的朋友。他被希腊英雄柏勒洛丰驯服，他允许柏勒洛丰骑着他和怪兽喀迈拉战斗。但当柏勒洛丰试着骑他前往奥林巴斯山时，牠让柏勒洛丰从他马背上摔下来。宙斯将他变成飞马座，放置在天空中。

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.