William of Rubruck (Dutch: Willem van Rubroeck; Latin: Gulielmus de Rubruquis; fl. 1248–1255) or Guillaume de Rubrouck was a Flemish Franciscan missionary and explorer.
He is best known for his travels to various parts of the Middle East and Central Asia in the 13th century, including the Mongol Empire. His account of his travels is one of the masterpieces of medieval travel literature, comparable to those of Marco Polo and Ibn Battuta.