Joseph Guy Marie Ropartz (June 15, 1864 – November 22, 1955) was a Breton composer and conductor. His compositions included five symphonies, three violin sonatas, cello sonatas, six string quartets, a piano trio and string trio (both in A minor), stage works, a number of choral works and other music including a Prélude, Marine et Chansons for flute, harp and string trio. Ropartz also published poetry.