Vice-Admiral Count Pierre Étienne René Marie Dumanoir Le Pelley was a French Navy officer, best known for commanding the vanguard of the French fleet at the Battle of Trafalgar. His conduct during this battle was the subject of controversy.

The Battle of Trafalgar was a naval engagement that took place on 21 October 1805 between the British Royal Navy and the combined fleets of the French and Spanish Navies during the War of the Third Coalition of the Napoleonic Wars (1803–1815).