Louis-Augustin Marmottin (March 11, 1875 at La Neuville-au-Pont (Marne) – May 9, 1960 at Reims (Marne)) was a French Catholic bishop. He was Bishop of Saint-Dié from 1930 to 1940 and then Archbishop of Reims from 1940 to 1960.
Louis-Augustin Marmottin was from a family of farmers of Marne. He completed secondary school studies at Saint-Étienne de Châlons-sur-Marne and then attended the grand seminary. He pursued higher studies at the Institut catholique de Paris from 1896 to 1898 and obtained a license in mathematics and a license in law.
Louis-Augustin Marmottin was ordained a priest December 17, 1898 for the Diocese of Châlons.
In 1930, Louis-Augustin Marmottin was named Bishop of the Diocese of Saint-Dié. He was ordained in the Cathedral Saint-Étienne de Châlons on October 20, 1930.
He obtained from Pope Pius XI the title of minor basilica for the Church of Saint-Maurice d'Epinal in 1933 and for the Church of Sainte-Jeanne d'Arc du Bois-Chenu in Domrémy-la-Pucelle in 1939.
He was named Archbishop of Reims on August 21, 1940, and took possession of the see on October 13, 1940.
He died May 9, 1960, after a long sickness and was interred in Reims Cathedral on 13.