Sunpadh or Sinbad was an 8th century Zoroastrian cleric who preached a syncretic heresy melding Islam and Zoroastrianism, and that Abu Muslim had not died, but would return with the Mahdi. Sunpadh was a friend and confidant of the Muslim general Abu Muslim, who had began the Abbasid revolt in 747 AD. After Abu Muslim had outlived his usefulness, the Abbasids betrayed and murdered him in 754 AD. This enraged Sinbad, who swore to march on Mecca and destroy the Holy Kaaba.

Because of this unusual and heretical vow, some believe Sunpadh was in fact a Zoroastrian, rather than a Muslim. His dogma received wide support among Iranian Shia, and revolts appeared in Rayy, Herat, and Sistan. His forces were defeated, and he was captured and killed.