Pierre-Charles-Jean-Baptiste-Silvestre de Villeneuve (31 December 1763 – 22 April 1806) was a French naval officer during the Napoleonic Wars. He was in command of the French and Spanish fleets defeated by Nelson at the battle of Trafalgar.

Villeneuve was born in 1763 at Valensole , Basses Alpes, and joined the French Navy in 1778. Although of aristocratic ancestry, he sympathised with the French Revolution, dropping the aristocratic "de" from his name and was able to continue his service in the Navy when other aristocratic officers were purged. He served during several battles, and was promoted to Rear Admiral in 1796 as a result of this.

At the battle of the Nile in 1798 he was in command of the rear division. His ship, Guillaume Tell, was only one of two French ships of the line to escape the defeat. He was captured soon afterwards when the British captured the island of Malta, but he was soon released. He was criticized for not engaging the British at the Nile, but Napoleon considered him a "lucky man" and his career was not affected.

In 1804, Napoleon ordered Villeneuve, now a Vice Admiral stationed at Toulon, to escape from the British blockade, overcome the British fleet in the English Channel, and allow the planned invasion of Britain to take place. To draw off the British defences, Villeneuve was to sail to the West Indies, where it was planned that he would combine with the Spanish fleet and the French fleet from Brest, attack British possessions in the Caribbean, before returning across the Atlantic to destroy the British Channel squadrons and escort the Armée d'Angleterre from their camp at Boulogne to victory in England.

After an abortive expedition in January, Villeneuve finally left Toulon on 29 March 1805 with eleven ships of the line. He evaded Nelson's blockade, passed the Strait of Gibraltar on 8 April and crossed the Atlantic with Nelson's fleet in pursuit, but about a month behind due to unfavourable winds. In the West Indies Villeneuve waited for a month at Martinique, but Admiral Ganteaume's Brest fleet did not appear. Eventually Villeneuve was pressured by French army officers into beginning the planned attack on the British, but he succeeded only in recapturing the island fort of Diamond Rock off Martinique. On 7 June he learned that Nelson had reached Antigua and on 11 June set out for Europe with Nelson again in pursuit.

On 22 July Villeneuve, now with twenty ships of the line and seven frigates, passed Cape Finisterre on the northwest coast of Spain and entered the Bay of Biscay. Here he met a British fleet of fifteen ships of the line commanded by Vice Admiral Sir Robert Calder. In the ensuing battle of Cape Finisterre, a confused action in bad visibility, the British, though outnumbered, were able to cut off and capture two Spanish ships. For two days Villeneuve shadowed the retreating British, but did not seek a battle. Instead he sailed to La Coruña, arriving on 1 August. Here he received orders from Napoleon to sail to Brest and Boulogne as planned. Instead, perhaps believing a false report of a superior British fleet in the Bay of Biscay, he sailed back to Cádiz, making the planned invasion of Britain wholly impossible.

At Cádiz the combined French and Spanish fleets were kept under blockade by Nelson. In September, Villeneuve was ordered to sail for Naples and attack British shipping in the Mediterranean, but he was initially unwilling to move. However, in mid-October he learned that Napoleon was about to replace him as commanding officer and order him to Paris to account for his actions (Napoleon had written to the Minister of Marine, "Villeneuve does not possess the strength of character to command a frigate. He lacks determination and has no moral courage"). Before his replacement could arrive, Villeneuve gave the order to sail on 18 October. Inexperienced crews and the difficulties of getting out of Cádiz meant that it took two days to get all 34 ships out of port and in some kind of order. On 21 October 1805 Villeneuve learned of the size of the British fleet, and turned back to Cádiz, but the combined fleets were intercepted by Nelson off Cape Trafalgar. Nelson, though outnumbered, won the battle of Trafalgar, and Villeneuve's flagship Bucentaure was captured along with many other French and Spanish ships.

Villeneuve was sent to England, but released on parole. He returned to France in 1806. On 22 April he was found dead at the Hotel de Patrie in Rennes, having been stabbed six times in the chest. A verdict of suicide was recorded, and he was buried without ceremony.

Historians have not been kind to Villeneuve. According to the 1911 Encyclopedia Britannica, "His decision to leave Cádiz and give battle in October 1805, which led directly to the battle of Trafalgar, cannot be justified even on his own principles. He foresaw defeat to be inevitable, and yet he went out solely because he learnt from the Minister of Marine that another officer had been sent to supersede him... It was provoked in a spasm of wounded vanity."