Peter Waldo was the leader of the Waldensians, a Christian spiritual movement of the Middle Ages.

The Waldensians, also known as Waldenses, Vallenses, Valdesi, or Vaudois, are adherents of a church tradition that began as an ascetic movement within Western Christianity before the Reformation. Originally known as the Poor of Lyon in the late twelfth century, the movement spread to the Cottian Alps in what is today France and Italy. The founding of the Waldensians is attributed to Peter Waldo, a wealthy merchant who gave away his property around 1173, preaching apostolic poverty as the way to perfection.