The Roman Catholic Archdiocese of Rennes, Dol, and Saint-Malo (Latin: Archidioecesis Rhedonensis, Dolensis et Sancti Maclovii; French: Archidiocèse de Rennes, Dol et Saint-Malo; Breton: Arc'heskopti Roazhon, Dol ha Sant-Maloù) is a diocese of the Latin Rite of the Roman Catholic Church in France. The diocese is coextensive with the department of Ille et Vilaine. The Archdiocese has 8 suffragans: the Diocese of Angers, the Diocese of Laval, the Diocese of Le Mans, the Diocese of Luçon, the Diocese of Nantes, the Diocese of Quimper and Léon, the Diocese of Saint-Brieuc and Tréguier, and the Diocese of Vannes.
In the Middle Ages the Bishop of Rennes had the privilege of crowning the dukes of Brittany in his cathedral. On the occasion of his first entry into Rennes it was customary for him to be borne on the shoulders of four Breton barons.
The Concordat of 1802 re-established the Diocese of Rennes which since then has included: the ancient Diocese of Rennes with the exception of three parishes given to the Diocese of Nantes; the greater part of the ancient Diocese of Dol; the greater part of the ancient Diocese of St. Malo; ten parishes that had formed part of the ancient Diocese of Vannes and Nantes. On 3 January 1859, the See of Rennes, which the French Revolution had desired to make a metropolitan, became an archiepiscopal see, with the Diocese of Quimper and Léon, Diocese of Vannes, and Diocese of St. Brieuc as suffragans. Cardinal Charles-Philippe Place obtained from Pope Leo XIII permission for the Archbishop of Rennes to add the titles of Dol and St. Malo to that of Rennes.
In 2014, in the Archdiocese of Rennes, Dol, and Saint-Malo there was one priest for every 2,537 Catholics.