The Sonata for flute, viola and harp (French: Sonate pour flûte, alto, et harpe), L. 137, was written by Claude Debussy in 1915.
The first performance of the Sonate took place in Boston, at Jordan Hall in the New England Conservatory, on November 7, 1916. The performers were members of a wind ensemble called the Longy Club, which had been founded by the principal oboist of the Boston Symphony Orchestra, George Longy. The first performance in France occurred on December 10, 1916, at the home of Debussy’s publisher, Jacques Durand”. The first public performance in France was thought to be at a charity concert on March 9, 1917 (Walker, 1988). However, Thompson (1968) reported a performance of the sonata at London's Aeolian Hall by Albert Fransella, H. Waldo Warner and Miriam Timothy on February 2, 1917 as part of a concert otherwise given by the London String Quartet. A typical performance lasts between 17 and 18 minutes.
According to Léon Vallas (1929, cited in Walker, 1988), Debussy initially planned this as a piece for flute, oboe and harp. He subsequently decided that the viola’s timbre would be a better combination for the flute than the oboe’s, so he changed the instrumentation to flute, viola and harp.