The Symphony No. 5½, A Symphony for Fun, is an orchestral symphony written in 1946 by the American composer Don Gillis. Gillis, a prolific composer, had already written five symphonies when he embarked on this work's composition. He stated that he originally set out to write his sixth symphony, but found that the music emerged so light-hearted in character that rather than give the symphony a conventional number he elected to publish it as no. 5½. The work is in four movements, the titles being punning references to the usual forms found in corresponding movements of "serious" symphonies.