John Lee Curtis "Sonny Boy" Williamson was an American blues harmonica player, singer and songwriter. He is often regarded as the pioneer of the blues harp as a solo instrument. He played on hundreds of recordings by many pre–World War II blues artists. Under his own name, he was one of the most recorded blues musicians of the 1930s and 1940s and is closely associated with Chicago producer Lester Melrose and Bluebird Records. His popular songs, original or adapted, include "Good Morning, School Girl", "Sugar Mama", "Early in the Morning", and "Stop Breaking Down".

"Good Morning, School Girl" is a blues standard that has been identified as an influential part of the blues canon. Pre-war Chicago blues vocalist and harmonica pioneer John Lee "Sonny Boy" Williamson first recorded it in 1937. Subsequently, a variety of artists have recorded versions of the song, usually calling it "Good Morning Little Schoolgirl".