Daniel Gregory Mason (born Nov. 20, 1873, Brookline, Mass., U.S.—died Dec. 4, 1953, Greenwich, Conn.) was a composer in the German-influenced Boston group of U.S. composers.
Mason was the grandson of the music publisher and educator Lowell Mason and the son of Henry Mason, a founder of the Mason & Hamlin Co. piano firm. He studied with John Knowles Paine at Harvard University and with Vincent d’Indy in Paris. From 1910 to 1942 he taught at Columbia University in New York City. His music is conservative in form, influenced strongly by the German Romantic composers; yet he also employed some devices of late 19th- and early 20th-century French and Russian Modernism. His works include three symphonies, chamber works, and the overture Chanticleer (1926), for which he is best remembered. He published several books of essays and teaching guides.