Jean Petit (Jehan Petit, John Parvus) (b. most likely at Brachy, Caux, in Normandy, and certainly in the Diocese of Rouen, c. 1360 − 15 July 1411) was a French theologian and professor in the University of Paris. He is known for his public defence of a political killing as tyrannicide.
Some historians (Duboulay, Luke Wadding) say he was a Franciscan, others that he was a Dominican: as a matter of fact, he never was a member of any religious order. He owed his education to the generosity of the Duke of Burgundy, who granted him a pension. In the first extant document that records his name, he is called Master of Arts (16 August 1385). Two years later his name occurs in the list sent by the University of Paris (31 July 1387) to Pope Clement VII, recommending its masters for vacant benefices.
He became a licentiate in theology in May 1400, and received the degree of Doctor before 1403, since he is mentioned in that year on the roll of the university as an active member of the theological faculty of Paris. In April 1407, he formed part of the embassy sent by Charles VI of France to urge Pope Benedict XIII and Pope Gregory XII to abdicate and thus reunite Christendom. This embassy had just returned to Paris, after a fruitless journey, when an event took place that gave Jean Petit a great notoriety in history.
On 23 November 1407, Louis I, Duke of Orléans, brother of Charles VI, was murdered by assassins in the pay of John the Fearless, Duke of Burgundy. The Duke of Orléans was unpopular with the people and was held responsible for the disorders and the taxations under which the kingdom groaned, during the madness of the king, his brother. The University of Paris was bitterly opposed to him for having renewed obedience to Benedict XIII.