Saint Guillaume de Donjon (†1209) was a French Roman Catholic prelate who served as the Archbishop of Bourges. He became a canon after his ordination to the priesthood and was known for his deep devotion to the Blessed Sacrament and for his conversion of sinners. It had been claimed that he performed eighteen miracles in life and a further eighteen in death. His canonization was celebrated under Pope Honorius III in 1218 and he was named as the patron saint for the Parisian college and gunsmiths.