Gaillard I de Durfort (Occitan: Galhart; fl. 1309–1356), known as the Archdeacon (l'Archidiacre), was a French priest and nobleman of the Durfort family. He inherited the Lacour–Durfort lands in 1345 and abandoned his clerical career to marry Marguerite de Caumont. At first he took the English side in the Hundred Years' War. As a commander, he played a major role in the campaigns of 1345–46 in the Duchy of Gascony. In 1352 he changed sides, but in 1356 he returned to the English side.