Johann Baptist Joseph Maximilian Reger (March 19, 1873 – May 11, 1916) was a German composer, conductor, pianist, organist, and teacher.

Born in Brand, Bavaria, Reger studied music in Munich and Wiesbaden with Hugo Riemann. From September 1901 he settled in Munich, where he obtained concert offers and where his rapid rise to fame began. During his first Munich season, Reger appeared in ten concerts as an organist, chamber pianist and accompanist. He continued to compose without interruption. From 1907 he worked in Leipzig, where he was music director of the university until 1908 and professor of composition at the conservatory until his death. It was during one of his weekly trips to Leipzig in 1916, to teach at the Conservatory, that he died of a heart attack at age 43. He was also active internationally as a conductor and pianist in that period of time. Among his students there were Joseph Haas, Jaroslav Kvapil, and George Szell.