Les petits riens ("The Little Nothings"; the lowercase in the original title is authentic) was a ballet in one act and three tableaux by Jean-Georges Noverre, with music by Wolfgang Amadeus Mozart, created at the Academie Royale de Music in Paris on 11 June 1778.
While Mozart was staying in Paris, Noverre asked him to compose a new score for a ballet that he had created in Vienna in 1767. The ballet was to be danced as an interlude in the new opera Le finte gemelle, by Niccolò Piccinni. The opera was a flop and closed after four performances. Although the ballet music was well-received, Mozart was not credited with it, and he was at the time little-known in Paris.
The score, catalogued as K299b, was thought lost, but it was rediscovered in the Paris Opera's archives in the late 19th century and has since entered both the ballet and symphonic repertoire.