Luc Urbain de Bouëxic, comte de Guichen (June 21, 1712, Fougères, Ille-et-Vilaine – January 13, 1790, Morlaix) was a French admiral who commanded the French fleets that fought the British at the First Battle of Ushant (1778) and the Battle of Martinique (1780) during the American War of Independence.
Guichen entered the navy in 1730 as "garde de la Marine," the first rank in the corps of royal officers. His promotion was not rapid. It was not till 1746 that he became "lieutenant de vaisseau", which was, however, a somewhat higher rank than the lieutenant in the British navy, since it carried with it the right to command a frigate. He was promoted "capitaine de vaisseau", or post captain, in May 1756. But his reputation must have been good, for he was made chevalier de Saint Louis in 1748.
In that year, 1748, de Guichen had fought no fewer than five battles against superior British forces, while escorting back to France, from the Antilles a huge convoy. In 1755 he participated in the abortive relief expedition to Louisbourg under Dubois de La Motte, and was involved, onboard L'Heros 70 off Louisbourg. In 1775 he was appointed to the frigate Terpsichore, attached to the training squadron, in which the duc de Chartres, afterwards notorious as the duc d'Orléans and as Philippe Egalité, was entered as volunteer. In the next year he was promoted Chef d'Escadre, or Rear-Admiral.
When France had become the ally of the Americans in the War of Independence, he hoisted his flag in the Channel fleet, and was present at the battle of Ushant on 27 July 1778, where his flagship, La Ville de Paris (90 guns) took station just abaft the fleet-flagship, La Bretagne, and several times fought off both Keppel, Palliser and other determined English assailants. For this deed he and his crew received the 'Cordon Rouge' for outstanding valour. In March 1779 he was promoted Lieutenant Général des Armées Navales, or roughly corresponding to the British Vice-Admiral of the White and Red and Admiral of the Blue and White. As such he commanded the French van in the Combined fleet of Comte d'Orvillers and Don Luis de Córdoba y Córdoba that year (June–September).