Carl-Johan Emanuel Vallgren (born 26 July 1964, in Linköping, Sweden) is a Swedish author, singer and musician. He won the August Prize in 2002 for the novel Den vidunderliga kärlekens historia, which was published in English translation as The Horrific Sufferings of the Mind-Reading Monster Hercules Barefoot.

Vallgren is of Finnish descent through his mother who was sent to Sweden as a Finnish war child during World War II.