Guillaume Briçonnet (1445–1514) was a French Cardinal and statesman.
Born at Tours, Guillaume Briçonnet was a younger son of Jean Briçonnet, Lord of Varennes, in Touraine, Secretary to the king and collector-general of Customs. Appointed Superintendent of Finances for the Province of Languedoc under Louis XI of France, Guillaume Briçonnet discharged the duties of his office with such integrity and efficiency, and showed himself so devoted to the interests of Louis that that monarch recommended him to his successor. Charles VIII of France made him Secretary of the Treasury, raised him to the first place in the Council of State, and, according to the historian Francesco Guicciardini, would undertake nothing in the government of his kingdom without the advice of Briçonnet.
Ludovico Sforza, called the Moor, wishing to dispossess his nephew of the Duchy of Milan, and finding himself opposed by Ferdinand I of Naples, sent an embassy under the Count of Belgiojoso to Charles to induce the French king to assert his claims to the Kingdom of Naples as heir to the house of Anjou. Sforza promised to place all his troops at the king's service. Briçonnet having shortly before this lost his wife, Raoulette de Beaune, by whom he had three sons, had entered the ecclesiastical state and been named Bishop of St.-Malo. To flatter his ambition the Milanese ambassadors assured him that the king's influence would raise him to the cardinalate. Briçonnet, thus won over to the Sforza interest, adroitly encouraged the warlike dispositions of his sovereign, triumphed over the opposition of the royal council, of the Duke of Bourbon, and of Anne of France, the Duke's wife, influenced Charles to sign a secret treaty with Sforza, and assured the king of his ability to raise the funds necessary to carry on the war both on land and sea.