The Rocker is a 2008 American comedy film directed by Peter Cattaneo and written by Maya Forbes and Wallace Wolodarsky, from a story by Ryan Jaffe. The film stars Rainn Wilson as a failed musician who goes on tour with his nephew's band after one of their songs goes viral. Christina Applegate, Jeff Garlin, Josh Gad, Teddy Geiger and Emma Stone also star.

The Rocker was released on August 20, 2008 to mixed reviews from critics, and was a box office bomb, that grossed just $6.6 million against a $15 million budget.

In late 1986, Vesuvius, a rock band from Cleveland, Ohio, performs at a local theater and is offered a recording contract. When their manager tells them they will get to tour as the opening act for Whitesnake, Vesuvius decides to replace drummer Robert "Fish" Fishman with the president of the record company's nephew.

20 years later, Vesuvius remains an immensely successful band, while Fish lives a relatively ordinary life. Matt Gadman, Fish's high school-aged nephew, plays keyboards in an alternative rock band called A.D.D., along with his friends Curtis Powell and Amelia Stone. The band is scheduled to play their school's prom, but the gig is in jeopardy when their drummer gets suspended from school. Matt convinces the others to allow Fish to fill in, but he ruins the gig when he launches into an impromptu drum solo. However, Fish is so excited by Curtis' songs and the chance to play again, he convinces them to let him join the band if he can deliver another gig. After repeated failed attempts, he finally succeeds in securing a gig at a club in Fort Wayne, Indiana. Because the other members are all minors, they have to sneak out to the gig but are apprehended in the process.

After Fish is forced to rent the basement of his favorite Chinese restaurant, the band invents a new way to practice via four-way iChat. To the dismay of his bandmates, Fish performs in the nude in an attempt to stay cool. The video of the practice quickly goes viral under the title of the "naked drummer band". The band is signed to a recording contract by the same label as Vesuvius and is sent on a Midwest tour. However, Fish commits stereotypical rockstar acts, despite the physical costs on his body, and vandalizes a hotel room, causing the band to be apprehended again.

After securing A.D.D.'s release, Kim, Curtis's mother, promises the other parents she will stay for the remainder of the tour, so Fish's antics will not influence their children.

The label asks A.D.D. to open a show for Vesuvius, honoring their induction into the Rock and Roll Hall of Fame. Fish refuses to play the gig and leaves the band, but Curtis eventually convinces him to put aside his resentment and play the show. After meeting Vesuvius before the show, Fish discovers that they have become vain and arrogant with faux British accents (except for the drummer who is English), and decides to wish Vesuvius good luck. Fish and the band perform to a standing ovation. After their gig, Amelia and Curtis, as well as Fish and Kim, begin a relationship. During Vesuvius's set, the lead singer's microphone falls off the stand while the voice track of their song continues, revealing that they have been lip-syncing. The audience chants an encore for A.D.D., performing for the crowd once again.

The Rocker was mostly filmed in Toronto, Ontario, Canada, with some exterior shots filmed in Cleveland, Ohio from July to September 2007.