Iranian mythology, or Persian mythology in western term, is the body of the myths originally told by ancient Persians and other Iranian peoples and a genre of ancient Persian folklore. These stories concern the origin and nature of the world, the lives and activities of deities, heroes, and mythological creatures, and the origins and significance of the ancient Persians' own cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of not only present-day Iran but of the Persosphere, which includes regions of West Asia, Central Asia, South Asia, and Transcaucasia where the culture of Iran has had significant influence. Historically, these were regions long ruled by dynasties of various Iranian empires, that incorporated considerable aspects of Persian culture through extensive contact with them, or where sufficient Iranian peoples settled to still maintain communities who patronize their respective cultures. It roughly corresponds to the Iranian Plateau and its bordering plains.

Zahhāk or Zahāk, also known as Zahhak the Snake Shoulder, is an evil figure in Persian mythology, evident in ancient Persian folklore as Azhi Dahāka, the name by which he also appears in the texts of the Avesta. In Middle Persian he is called Dahāg or Bēvar Asp the latter meaning "he who has 10,000 horses". In Zoroastrianism, Zahhak is considered the son of Ahriman, the foe of Ahura Mazda. In the Shāhnāmeh of Ferdowsi, Zahhāk is the son of a ruler named Merdās.