John Vianney (born Jean-Marie Vianney and later Jean-Marie-Baptiste Vianney; 8 May 1786 – 4 August 1859) was a French Catholic priest often referred to as the Curé d'Ars ("the parish priest of Ars"). He is known for his priestly and pastoral work in his parish in Ars, France, resulting in the radical spiritual transformation of the community and its surroundings.

Catholics note his saintly life, mortification, persevering ministry in the sacrament of confession, and ardent devotion to the Blessed Virgin Mary. He was canonized in 1925 and his feast day is August 4. He is the patron saint of parish priests.