Félix Augustin Joseph Vasseur, known as Léon Vasseur (28 May 1844 – 25 May 1917), was a French composer, organist and conductor. While working as a cathedral organist, he turned to composing operettas and soon had a hit with La timbale d'argent (1872). He wrote another thirty operettas but never repeated that early success. He also composed church music including two settings of the mass.