Armand Augustin Louis de Caulaincourt (December 9, 1773 – February 19, 1827) French general and diplomat, was born of a noble family.

In his fifteenth year Caulaincourt entered the army, but did not achieve a high degree of success. In 1792 he was captain, but he was thrown into prison—probably because he had rendered himself obnoxious to the democrats. He was freed, but on condition that he should serve as a simple grenadier. He did so for three years, when, through the intercession of General Hoche, he was restored to his former rank as captain. Yet even after ten years of service, his advancements were very slow.

He eventually attained the rank of colonel in the Army of the Rhine in 1799–1800. After the peace of Lunéville in 1801 he was sent to St Petersburg by Napoleon I of France. His mission was ostensibly to compliment Alexander I on his accession to the crown, but in reality to destroy the English influence in that court.

On his return he was named aide-de-camp of the First Consul. He was employed to seize some agents of the English government in Baden in 1804, which led to the accusation that he was implicated in the arrest of the duc d'Enghien, which he vigorously denied. After the establishment of the empire he received various honors and the title of Duke of Vicenza in 1808. Napoleon sent him in 1807 as an ambassador to St. Petersburg, where Caulaincourt tried to maintain the alliance of Tilsit. His tasks were more those of a spy than an ambassador, and although Napoleon's ambition made the task a difficult one, Caulaincourt succeeded in it for some years.

In 1810 Caulaincourt strongly advised Napoleon to renounce his proposed expedition to Russia. During the war he accompanied the emperor, and was one of those whom Napoleon took along with him when he suddenly abandoned his army in Poland to return to Paris in December of 1812. During the last years of the empire, Caulaincourt was charged with all the diplomatic negotiations. He signed the armistice of Pleswitz , June 1813, represented France at the congress of Prague in August 1813, and at the treaty of Fontainebleu on April 10, 1814.

During the first Restoration, Caulaincourt lived in obscure retirement. When Napoleon returned from Elba, he became minister of foreign affairs, and tried to persuade Europe of the emperor's peaceful intentions. After the second Restoration, Caulaincourt's name was on the list of those proscribed, but it was erased on the personal intervention of Alexander I with Louis XVIII.

Caulaincourt's memoirs appeared under the title Souvenirs du duc de Vicence in 1837–1840. See Albert Vandal, Napoleon et Alexandre (Paris, 1891–1895); Tatischeff, Alexandre I et Napoleon (Paris, 1892); H Houssaye, 1814 (Paris, 1888), and 1815 (Paris, 1893).