Louis-Esprit d'Aymar was a French Navy officer. He fought in the Indian Ocean under Suffren during the American Revolutionary War, captaining the 64-gun at the Battle of Trincomalee from 25 August to 3 September 1782, and the 74-gun at the Battle of Cuddalore on 20 June 1783.
The Chevalier d'Aymar was born to the family of a treasurer from Aix-en-Provence. He joined the French Navy as a Garde-Marine on 29 September 1749. He was promoted to lieutenant on 1 May 1763, and to captain on 4 April 1777.
d'Aymar took part in the Battle of Martinique, on 17 April 1780, at the command of . Along with and , Saint Michel directly engaged the much stronger British , under Rodney, and . Being smallest of the ship, Saint Michel sustained especially heavy damage, and d'Aymar had his right arm shot away by a cannonball.
d'Aymar left France in November 1781 at the command of Saint Michel, part of a division also comprising the 74-gun , the frigate . The division made in junction with Suffren's squadron at Batacalo on 9 August 1782. He captained the 64-gun Saint Michel at the Battle of Trincomalee from 25 August to 3 September 1782. When Suffren reshuffled his captains after the battle, he promoted d'Aymar to the 74-gun . D'Aymar commanded her at the Battle of Cuddalore on 20 June 1783.
After the war, he was amongst the captains that Suffren recommended for promotion. He received a 600-livre pension in recognition of his service.
In 1791, after the duel between Lameth and Castries, d'Aymar publicly regretted that Castries had not killed Lameth. A crowd then brutalised d'Aymar.
D'Aymar was promoted to rear admiral on 1 January 1792.