Antoine Nompar de Caumont, duc de Lauzun (1632 – November 19, 1723) was a French courtier and soldier. He was the only love interest of the "greatest heiress in Europe", Anne Marie Louise d'Orléans, Duchess of Montpensier, cousin of Louis XIV.
He was the son of Gabriel, comte de Lauzun, and his wife Charlotte, daughter of Henri-Nompar de Caumont, duc de La Force. He was brought up with the children of his relative, the maréchal de Gramont. One daughter, Catherine Charlotte, afterwards princess of Monaco by marriage to Louis I Grimaldi, was the object of the one passion of Lauzun's life.
He entered the army, and served under Turenne, also his kinsman, and in 1655 succeeded his father as commander of the cent gentilshommes de la maison de roi. Then known as the comte de Puyguilhem (or Péguilin, as contemporaries simplified his name), he rose rapidly in Louis XIV's favour, became colonel of the royal regiment of dragoons, and was gazetted maréchal de camp. He and Madame de Monaco belonged to the côterie of the young Duchess of Orléans. His rough wit and skill in practical jokes pleased Louis XIV, but his jealousy and violence were the causes of his undoing. He prevented a meeting between Louis XIV and Madame de Monaco, and it was jealousy in this matter, rather than hostility to Louise de la Vallière, which led him to promote Madame de Montespan's intrigues with the king. He asked this lady to secure for him the post of grand-master of the artillery, and on Louis's refusal to give him the appointment he turned his back on the king, broke his sword, and swore that never again would he serve a monarch who had broken his word. The result was a short sojourn in the Bastille, but he soon returned to his function as court buffoon.