John La Montaine (b. March 17, 1920) is an American composer, born in Oak Park, Illinois, who won the 1959 Pulitzer Prize for Music for his Piano Concerto no. 1, Op. 9, "In Time of War" (1958), which was premiered by Jorge Bolet.
His teachers included Howard Hanson, Bernard Rogers, and Nadia Boulanger. His works have been performed by Jessye Norman and Jorge Bolet.
In honor of the American Bicentennial celebration in 1976, he was commissioned to create a choral work for the Penn State Institute for Arts and Humanistic Studies. The opera, entitled "Be Glad Then America" was performed by the University Choirs, under the direction of Sarah Caldwell. The folk singer Odetta appeared as the Muse for America.
La Montaine lives in Hollywood, Los Angeles, California. His publisher, Fredonia Press, is named for the street on which he lives. His business partner was the composer and pianist Paul J. Sifler (1911-2001).