Reginald of Bar, also known as Renaud de Mouçon, was bishop of Chartres from 1182 until his death in 1217. His parents were Reginald II of Bar and his wife Adèle de Champagne. Via his mother he was first cousin to king Philip II of France, who facilitated his career. He was named canon and treasurer of Saint-Martin de Tours and was then elected bishop of Chartres in 1182. He played an important role in France and Champagne and participated in the Third Crusade.