Marguerite-Élie Guadet (20 July 1758 – 17 June 1794) was a French political figure of the Revolutionary period.
Born in Saint-Émilion, Gironde, Aquitaine, he had already gained a reputation as a lawyer in Bordeaux by the time of the Revolution. In 1790 he was made administrator of the Gironde, and in 1791 president of the criminal tribunal, being elected to the Legislative Assembly as one of the group of deputies known subsequently as Girondists.
As a supporter of the monarchist and liberal constitution of 1791 he joined the Jacobin Club, and here and in the Assembly became an eloquent advocate of all the measures directed against real or supposed traitors to the Constitution.
He strongly opposed the ministers of King Louis XVI, and was largely instrumental in forcing the king to accept the Girondist ministry of 15 March 1792. He supported the policy of forcing Louis XVI into harmony with the Revolution, and moved (3 May) for the dismissal of the king's non-juring confessor, for the banishment of all non-juring priests (16 May), for the disbandment of the royal guard (30 May), and the formation in Paris of a camp des fédérés (4 June).
Nevertheless, he remained a Royalist, and, with Armand Gensonné and Pierre Victurnien Vergniaud, even addressed a letter to the king soliciting a private interview. Whatever negotiations may have resulted, however, were cut short by the insurrection of 10 August. Guadet, who presided over the Assembly during part of the rebellion day, placed himself into strong opposition to the insurrectionary Paris Commune, and it was on his motion that on 30 August the Assembly voted its dissolution — a decision reversed on the following day. In September, Guadet was returned by a large majority as deputy to the National Convention.