Gaston Dethier

Gaston Dethier (19 April 1875, Liège, Belgium — 26 May 1958, New York) was a Belgian-American organist, pianist, composer, and music educator, brother of violinist Édouard Dethier (1885—1962), and uncle of physiologist and entomologist Vincent Dethier (1915—1993). He taught at the Juilliard School between 1907 and 1945.

Dethier originated from a prolific musical family, son of organist Emile Jean Joseph Dethier (1849—1933), and all six of his brothers and sisters also became musicians. Gaston-Marie studied at Juilliard School with Alexandre Guilmant. In 1886, eleven-year-old Gaston became an organist at the St. Jacques le Mineur church in his hometown, Liège.

In 1894, Dethier immigrated to the United States and subsequently naturalized as a citizen. He served as the organist at Juilliard School in Manhattan from 1894 until 1907 before joining a recently established Institute of Musical Art (renamed Juilliard School in 1926) as the head of the organ department. Gaston Dethier taught at Juilliard for the next 38 years, and some of his notable students include Carl McKinley, Powell Weaver, Georges-Émile Tanguay, Ray Lev, and Lilian Carpenter. He was a prolific composer, but most of his works written for organ remains obscure. Dethier's best-known composition, Variations On "Adeste Fideles," was popularized by Virgil Fox and subsequently became one of the Christmas organ "standards."