Louis Antoine de Bougainville (November 11, 1729 - August 31, 1811) was a French navigator.

De Bougainville was born in Paris, France, the son of a notary. In early life, he studied law, but soon abandoned the profession, and in 1753 entered the army in the corps of musketeers. At the age of twenty-five he published a treatise on the integral calculus, as a supplement to De l'Hôpital's treatise, Des infiniment petits.

In 1755 he was sent to London as secretary to the French embassy, and was made a member of the Royal Society. In 1756 he went to Canada as captain of dragoons and aide-de-camp to the Marquis de Montcalm. He took an active part in the campaigns of 1756 (Fort Oswego) and 1757 (Fort William Henry). He was wounded in 1758 at the successful defense of Fort Carillon. He sailed back to France the following winter, under orders from the marquis to obtain additional military resources for the colony; during this crossing, he continued familiarizing himself with the ways of the sea, skills that would latter serve him well. Having distinguished himself in the war against England, he was rewarded with the cross of St Louis and returned to Canada the following year with the rank of colonel, but with little supplies to show for his trip - the metropolitan authorities having decided that "When the house is on fire, one does not worry about the stables".

During the pivotal year of 1759 (see Seven Years War and French and Indian War), he participated in the defense of the capital of New France, the fortified Quebec City. With a small elite troop under his command, among which the Grenadiers and the Volontaires à cheval, he patrolled the north shore of the St. Lawrence River, upstream from the city, all summer long stopping the British several times from landing and thus cutting communications with Montreal. He was not given sufficient time, however, to rally his troops and attack the British rear when they successfully climbed up to the Plains of Abraham and attacked Quebec on September 13.

Following the death of the Marquis de Montcalm and the fall of Québec on September 18 - after the colonel's aborted attempt to resupply the besieged city - De Bougainville was dispached to the western front by his new commanding officer, General de Levis and attempted to stop the British advance from his entrenchments at Isle-aux-Noix. He was among the officers that accompanied de Levis to Isle St. Helen for the final holdout before the general capitulation of 1761.

Shipped back to Europe along with the other French officers, all deprived of military honours by the victors, De Bougainville was prohibited to take up any further active duty against the British under the terms of surrender. He spent the remainding years of the Seven Years War (1761 to 1763) as a diplomat and helped negotiate the Treaty of Paris that eventually conceded most of New France to the British Empire.

After the peace, when the French government conceived the project of colonizing the Falkland Islands, Bougainville undertook the task at his own expense. But the settlement having excited the jealousy of Spain, the French government gave it up to them, on condition of their advantage of the easterly monsoon, which carried them to Batavia. In March 1769 the expedition arrived at St Malo, with the loss of only seven out of upwards of 200 men. Bougainville's account of the voyage (Paris, 1771) is written with simplicity and some humour.

After an interval of several years, he again accepted a naval command and saw much active service between 1779 and 1782. In the memorable engagement of the April 12, 1782, in which Admiral George Rodney defeated the Comte de Grasse, near Martinique, Bougainville, who commanded the Auguste, succeeded in rallying eight ships of his own division, and bringing them safely into Saint Eustace. He was promoted to chef d'escadre, and on reentering the army, was given the rank of marechal de camp. After the peace he returned to Paris, and obtained the place of associate of the Academy. He projected a voyage of discovery towards the north pole, but this did not meet with support from the French government.

Bougainville obtained the rank of vice-admiral in 1791; and in 1792, having escaped almost miraculously from the massacres of Paris, he retired to his estate in Normandy. He was chosen a member of the Institute at its formation, and returning to Paris became a member of the Board of Longitude. In his old age Napoleon I made him a senator, count of the empire, and member of the Legion of Honour. He died in Paris on the August 31, 1811. He was married and had three sons, who served in the French army.

Bougainville's name is given to the largest member of the Solomon Islands; and to the strait which divides it from the island of Choiseul. It is also applied to the strait between Mallicollo and Espiritu Santo islands of the New Hebrides group, and the South American climbing plant bougainvillea, often cultivated in greenhouses, is named after him.