Avenue Q is a Tony award-winning musical that was conceived by Robert Lopez and Jeff Marx, who wrote the music and lyrics. The book is by Jeff Whitty. The show was produced by and opened at the Off-Broadway Vineyard Theatre in March 2003. The show was directed by Jason Moore. The production then transferred to Broadway in July 2003 and won several Tony Awards, including the award for Best Musical. It is still running on Broadway and currently holds the position of 30th longest running musical in Broadway history. The show has spawned a 2005 Las Vegas production, a 2006 West End production and various international productions. A U.S. national tour began in July 2007.

The show is largely inspired by (and is in the style of) Sesame Street: Most of the characters in the show are puppets (operated by actors onstage), the set depicts several tenements on a rundown street in an "outer borough" of New York City, both the live characters and puppet characters sing, and short animated video clips are played as part of the story. Also, several characters are recognizably parodies of classic Sesame Street characters: for example, the roommates Rod and Nicky are versions of Sesame Street's Bert and Ernie, and Trekkie Monster is based on Cookie Monster. However, the characters are in their twenties and thirties and face adult problems instead of those faced by pre-schoolers. The characters use profanity, and the songs concern adult themes. A recurring theme is the central character's search for a "purpose."