Sir Jacques le Gris (lit. "the Gray") (c. 1330s – 29 December 1386) was a French squire and knight who gained fame and infamy, and was ultimately killed when he engaged in the last judicial duel permitted by the Parlement of Paris after he was accused of rape by Marguerite de Carrouges, the wife of his neighbour and rival, Sir Jean de Carrouges. Carrouges brought legal proceedings against Le Gris before King Charles VI who after hearing the evidence, authorised a trial by combat to determine the question. The duel attracted thousands of spectators and has been discussed by many notable French writers, from the contemporary Jean Froissart to Voltaire.

Described as a large and physically imposing man, and rumoured to be a womaniser, Le Gris was a liegeman (feudal retainer) of Count Pierre d'Alençon and a favourite at his court, governing a large swathe of his liege lord's territory, in addition to his own ancestral holdings. Le Gris' insistence on defending his case by chivalric trial by combat, rather than opting for the safer church trial (to which, as a cleric in minor orders, he was entitled), attracted widespread support for his cause amongst the French nobility. Controversy continues to this day as to where the real guilt lies in the case.