Léonor d'Orléans (1540 – 7 August 1573) was duc de Longueville, prince of Châtellaillon, marquis of Rothelin, count of Montgommery and of Tancarville, visount of Abberville, Melun, count of Neufchâtel and of Valangin, was governor of Picardy and Normandy and one of the military leaders of the French Wars of Religion. He was the grandson of Louis I d'Orléans, duc de Longueville and he succeeded his first cousin, François III d'Orléans as duc de Longueville.
He married Marie de Bourbon, Duchess of Estouteville (1539–1601), daughter of François I Bourbon (1491-1545) and Adrienne d’Estouteville (1512-1560), and was father to:
He died at Blois and was buried at Châteaudun.