Anne-Pierre, marquis de Montesquiou-Fézensac (17 October 1739 – 30 December 1798) was a French general and writer.
He was born in Paris, of an ancient family of Armagnac. He was brought up with the children of the king of France, and showed some taste for letters. He entered the army in 1754, was successively colonel of the Grenadiers and the Royal-Vaissaux regiment, and in 1780 was made maréchal-de-camp. Some pieces of verse and several comedies gained him admission to the Académie française in 1784. He was elected deputy to the Estates-General of 1789 by the nobles of Paris, and, animated by Liberal ideas, he soon joined the Third Estate, and seconded Necker's financial schemes.
He served on the committee charged with the issue of assignats, and was named president of the Constituent Assembly on 14 March 1791. In May 1791 he was promoted lieutenant-general, served under Lafayette, and in February 1792 was given the command of the Army of the South. In September of the same year he completed the conquest of Savoy, but in November 1792 he was accused of royalist leanings, and had to take refuge in Switzerland. In 1795 his name was erased from the list of emigrés and he returned to Paris, where he died on 30 December 1798.