Manso I or II was the Prefect of Amalfi from 898 to 914.
He succeeded, or may have deposed, Stephen, a relative of the first ruling family, and to whom he was unrelated. In 900, he associated his son Mastalus with him, following a practice that was to become widespread in the Mezzogiorno. He retired to the monastery of Saint Benedict of Nursia in Scala, leaving Amalfi to his son, the first judge.