Juliette Nadia Boulanger (French: [ʒyljɛt nadja bulɑ̃ʒe] ; 16 September 1887 – 22 October 1979) was a French music teacher, conductor and composer. She taught many of the leading composers and musicians of the 20th century, and also performed occasionally as a pianist and organist.
From a musical family, she achieved early honours as a student at the Conservatoire de Paris but, believing that she had no particular talent as a composer, she gave up writing music and became a teacher. In that capacity, she influenced generations of young composers, especially those from the United States and other English-speaking countries. Among her students were many important composers, soloists, arrangers, and conductors, including Grażyna Bacewicz, Daniel Barenboim, Lennox Berkeley, İdil Biret, Elliott Carter, Aaron Copland, David Diamond, John Eliot Gardiner, Philip Glass, Roy Harris, Quincy Jones, Gilbert Levine, Dinu Lipatti, Igor Markevitch, Julia Perry, Astor Piazzolla, Laurence Rosenthal, and over 250 others.