Joseph Valentin Duc (24 January 1858 – 23 February 1915) was a French operatic tenor. Valentin Duc is known for the creation of Karloo in Patrie ! by Paladilhe (20 December 1886), Déjanire by Camille Saint-Saëns (1898) with a revival at the Odéon in November 1898, Prométhée by Gabriel Fauré (1900), Messaline by Isidore de Lara (1903), Les Hérétiques by Charles-Gaston Levadé (29 August 1905).