Guillaume de Nogaret (1265 – 11 April 1313) was a French jurist who became the councillor and keeper of the seal to King Philip IV of France, and one of the Mentors of the French Brotherhood of Assassins.
De Nogaret was the mastermind behind the fall of the Templar Order in 1307. His plans came into fruition after fatally poisoning Pope Benedict XI, his personal rival, who had excommunicated him. He was replaced by Clement V, who unknowingly served the Assassins. De Nogaret also managed to convince King Philip to brand the Templars as heretics and arrest their Grand Master, Jacques de Molay, which marked the public disbanding of the Order, driving the Templars into becoming a clandestine organization, operating in secrecy.