Thomas Wright "Fats" Waller (May 21, 1904 – December 15, 1943) was an American jazz pianist, organist, composer, and singer. His innovations in the Harlem stride style laid much of the basis for modern jazz piano. A widely popular star in the jazz and swing eras, he toured internationally, achieving critical and commercial success in the United States and Europe. His best-known compositions, "Ain't Misbehavin'" and "Honeysuckle Rose", were inducted into the Grammy Hall of Fame in 1984 and 1999.

Waller copyrighted over 400 songs, many of them co-written with his closest collaborator, Andy Razaf. Razaf described his partner as "the soul of melody... a man who made the piano sing... both big in body and in mind... known for his generosity... a bubbling bundle of joy". It is likely that he composed many more popular songs than he has been credited with: when in financial difficulties he had a habit of selling songs to other writers and performers who claimed them as their own. He died from pneumonia, aged 39.