Jean de La Grange (a.k.a. Jean de Lagrange) (c.1325 – April 25, 1402) was a French prelate and politician, active during the reigns of Charles V and Charles VI, and an important member of the papal curia at Avignon, at the time of the Western Schism. He was the brother of Étienne de La Grange, an advisor to the king and president of Parlement.
A Benedictine monk, he was successively Prior of Élancourt, then of Gigny, and ultimately procurator of the Cluniac Order. He became abbot of Fécamp in 1358 and joined the Council of King Charles V after having been in the entourage of Charles the Bad. Within the Council, he was in charge of ecclesiastical affairs but also was involved in financial and fiscal issues. In 1370, the king named him president of the Cour des Aides. He was named bishop of Amiens (1373), then cardinal-bishop with the title of Saint-Marcel (1375).
La Grange became a counsellor of Gregory XI (c 1336-78), the French-born pope who ended the period during which the papacy was located in Avignon, France (the so-called Babylonian Captivity) by returning to Rome in 1378. When Gregory died the following year, however, La Grange arrived in Rome too late to take part in the Conclave that elected his successor, Pope Urban VI, an Italian. In protest at the election of a non-French pope, La Grange joined other French Cardinals in re-convening the Conclave in Fondi and elected a rival pope, Clement VII, the first of the so-called Antipopes.