Mustafa I (1592- January 20, 1639) was the sultan of the Ottoman Empire from 1617 to 1618 and from 1622 to 1623. The brother of Ahmed I, Mustafa was reported to be mentally retarded or at least neurotic and was never more than a tool of court cliques at the Topkapi Palace. During the reign of his brother, he was confined to his room in virtual imprisonment for fourteen years.

In 1618 he was deposed in favour of his young nephew Osman II, and after Osman's murder in 1622 he again took the throne for another year. He was finally deposed and imprisoned by Osman's brother Murad IV. He would die sixteen years later.