Georges C. Mager (1885–1950) was a French musician, and principal trumpet with the Boston Symphony Orchestra from 1919 until his death in 1950. He was a renowned trumpeter in Paris before the First World War, playing at the Paris Opera, Concerts Lamoureux, and the Concerts of the Society of the Conservatory. He also had an alternate career as a singer in the duo with his wife Claire, a well-known soprano, and had hoped for an operatic career. After serving in the French army during the war he came to America as flugelhorn soloist with the Garde Republicaine Band and was engaged to play in the Boston Symphony, first as a violist, since there was no vacancy for trumpet, sharing a stand with Arthur Fiedler. He assumed the first trumpet position in 1920. Trained in France, he was a student of J. Mellet (a student of Jean-Baptiste Arban) at the Paris Conservatory. He was an advocate of use of the C trumpet as an orchestral instrument and had great influence on its development and acceptance in America, working most notably with Vincent Bach. He also was the first trumpeter in America to play Bach's Brandenburg Concerto in the original high tessitura.