"Monster in the Mirror" is a song performed by Grover, a Muppet character from the PBS television series Sesame Street. Copyrighted in 1989, the song was composed by Christopher Cerf and Norman Stiles.
In the song, Grover first sees a monster in the mirror before realizing the monster is himself, a theme repeated from the 1971 book The Monster at the End of This Book: Starring Lovable, Furry Old Grover. A music video for the song premiered in 1991 in the television special Big Bird's Birthday or Let Me Eat Cake, featuring 25 celebrities including Ray Charles, Robin Williams, Whoopi Goldberg, Julia Roberts, and the Simpson family.
Los Angeles Times reviewer David Zurawik called the celebrity music video "the happiest two minutes of film that I've ever seen".