"Fever" is a song written by Eddie Cooley and Otis Blackwell, who used the pseudonym John Davenport. It was originally recorded by American R&B singer Little Willie John for his debut album, Fever.

It has been covered by numerous artists from various musical genres, most notably by Peggy Lee, whose 1958 rendition became the most widely known version of "Fever" and the singer's signature song. Lee's version contained rewritten lyrics different from the original and an altered music arrangement. It became a top-five hit on the music charts in the UK and Australia in addition to entering the top ten in the US and the Netherlands. "Fever" was nominated in three categories at the 1st Annual Grammy Awards in 1959, including Record of the Year and Song of the Year.