Jean-Josaphat Gagnier (2 December 1885 – 16 September 1949) was a Canadian conductor, composer, clarinetist, bassoonist, pianist, arts administrator, and music educator. His compositional output mainly consists of works for orchestra and band, although he did write some choral pieces, songs, works for solo piano and organ, some incidental music for the theatre, and a work for solo harp. His compositions are written in a wide variety of styles from romanticism to impressionism to 20th century idioms.