André Charles Prosper Messager (French: [mɛsaʒe]; 30 December 1853 – 24 February 1929) was a French composer, organist, pianist, conductor and administrator. His stage compositions included ballets and 30 opéra comiques and operettas, among which Véronique had lasting success, with Les p'tites Michu and Monsieur Beaucaire also enjoying international success.
Despite financial obstacles, Messager pursued studies in piano and composition, with teachers including Camille Saint-Saëns and Gabriel Fauré. He became a major figure in the musical life of London as well as Paris, both as a conductor and a composer. Most of his Parisian works were produced in London, where several of them had long runs and numerous revivals, and he wrote two operatic works in English. He was the only French composer to write an original Savoy opera. Towards the end of his career, he composed musical comedies for Sacha Guitry and Yvonne Printemps.
As a conductor, Messager held prominent positions in Paris and London, at the head of the Opéra-Comique, the Paris Opéra, the Orchestre de la Société des Concerts du Conservatoire, and of the Royal Opera House, Covent Garden. Although as a composer he is known chiefly for his light works, as a conductor he presented a wide range of operas, from Mozart to Richard Strauss, and he acquired a reputation as a conductor of Wagner. In Paris he conducted the world premieres of Debussy's Pelléas et Mélisande, Massenet's Grisélidis and Charpentier's Louise. At Covent Garden, he gave the British premieres of operas by Saint-Saëns and Massenet.