Louis-Marie Grignion de Montfort est un prêtre catholique français, né le 31 janvier 1673 à Montfort-la-Cane en province de Bretagne (aujourd'hui Montfort-sur-Meu en Ille-et-Vilaine) et qui est mort le 28 avril 1716 à Saint-Laurent-sur-Sèvre en province du Poitou) (de nos jours dans le département de la Vendée). Il est le fondateur de deux congrégations religieuses : la Compagnie de Marie (les Pères montfortains) d'où seront issus les Frères de Saint-Gabriel et une congrégation féminine : les Filles de la sagesse. Béatifié par Léon XIII, en 1888, il est canonisé par Pie XII, en 1947.

Saint Louis-Marie Grignion de Montfort (31 January 1673 – 28 April 1716) was a French Roman Catholic priest and Confessor. He was known in his time as a preacher and was made a missionary apostolic by Pope Clement XI.

As well as preaching, Montfort found time to write a number of books which went on to become classic Catholic titles and influenced several popes. Montfort is known for his particular devotion to the Blessed Virgin Mary and the practice of praying the Rosary.

Montfort is considered as one of the early writers in the field of Mariology. His most notable works regarding Marian devotions are contained in The Secret of Mary and the True Devotion to Mary.

The Roman Catholic Church, under the pontificate of Pope Pius XII canonized Montfort on July 20, 1947. A "founders statue" created by Giacomo Parisini is located in an upper niche of the south nave of Saint Peter's Basilica.