The Adventures of Elmo in Grouchland is a 1999 American musical adventure comedy film directed by Gary Halvorson in his feature film debut. This was the second of the two theatrical feature films to be based on the children's television series Sesame Street, after Sesame Street Presents: Follow That Bird. It stars Mandy Patinkin and Vanessa Williams alongside Muppet performers Kevin Clash, Caroll Spinney, Steve Whitmire, and Frank Oz.

Produced by Jim Henson Pictures and Children's Television Workshop, the film was released by Columbia Pictures on October 1, 1999. The film received generally positive reviews from critics, but was a box office bomb, grossing $12 million against a budget of more than $26 million.

The film was one of the few Sesame Street productions directly produced by The Jim Henson Company. This was the final Muppet feature film to involve Oz, who retired from being a full-time puppeteer the following year. This was also the final theatrically released film to predominately feature Muppet characters until Walt Disney Pictures' The Muppets in 2011, and the final Muppet film to feature Caroll Spinney before his retirement in 2018 and his death in 2019.