Marcel Sembat (19 October 1862 – 5 September 1922) was a French Socialist politician. He served as a member of the National Assembly of France from 1893 to 1922, and as Minister of Public Works from August 26, 1914 to December 12, 1916.
Marcel Sembat was born on October 19, 1862 in Bonnières-sur-Seine, Seine-et-Oise, France. He went to school in Mantes-la-Jolie, attended the Collège Stanislas in Paris and later received a PhD in Law.
He started a career in journalism and co-founded the Revue de l'évolution. From 1890 to 1897, he was the editor of La Petite République, created by Leon Gambetta. It was then that he became a Socialist. He also wrote for La Revue socialiste, La Revue de l'enseignement primaire, Documents du Progrès, La Lanterne, Petit sou and Paris-Journal. He later became an editor of L'Humanité.
He served as member of the Chamber of Deputies of France from 1893 to 1922. A socialist, he supported workers' rights during strikes. He oversaw the construction of telephone cables from Brest, France to Dakar, Senegal. He supported Algerians against French colonialists in French Algeria. He was opposed to the presence of French Christian missionaries in China.