"When It's Sleepy Time Down South", also known as "Sleepy Time Down South", is a 1931 jazz song written by Clarence Muse, Leon René and Otis René. It was sung in the movie Safe in Hell by Nina Mae McKinney, and became the signature song of Louis Armstrong, who recorded it almost a hundred times during his career. The song is now considered a jazz standard.
Al Hirt released a version on his 1963 album, Our Man in New Orleans, and Harry James released a version on his 1972 album Mr. Trumpet (Longines Symphonette Society SYS 5459/LS 217C/LS 217U).
Bing Crosby recorded the song in 1975 for his album A Southern Memoir.
The lyrics concern the Great Migration in the United States, the movement of African Americans from the South to cities in the North, with the singer talking about the "dear old Southland... where I belong", and contain many racial stereotypes. Armstrong's popularity among African-American audiences dropped because of the song, but at the same time it helped the trumpeter to make his fan base broader. There is a 1942 film short of the song where Armstrong and others played slaves and farm workers.