Rowlf is a muppet musician from Jim Henson's The Muppet Show. He is the Muppet theater's resident pianist, and occasionally also performs with the band The Electric Mayhem. He is a scruffy, brown, dog of indeterminate breed with a bulbous black nose and long floppy ears.

He's a quiet fellow, and very easygoing. When the band walked out over the lameness of the theme song once, only Rowlf stayed on, playing it singlehandedly. He once sang a touching song to a puppy, and he plays a wisecracking doctor in a recurring medical drama parody skit, with nurses Janice and Piggy.

Rowlf and Kermit the Frog were Jim Henson's first two Muppets in the 1950s, created out of scraps of cloth and fur and other odds and ends. Although Kermit the Frog is often credited as the icon of Jim Henson's Muppets, Rowlf was actually the first true Muppet "star" as a recurring character on The Jimmy Dean show.

Rowlf was later incorporated into Muppet Babies as a toy-piano-playing puppy in a diaper and a white bib with a red musical note on it.

Rowlf was considered to be one of Jim Henson's most personal characters, and has been mostly retired since Jim Henson's death in 1990, similar to how Scooter was retired after Richard Hunt's death in 1992. It's a Very Merry Muppet Christmas Movie, however, contains the first spoken lines by Rowlf since the death of Jim Henson. It was reputed that Rowlf was Jim Henson's favorite character.