High school students Olivia White (Bridgit Mendler), Mohini "Mo" Banjaree (Naomi Scott), Charles "Charlie" Delgado (Blake Michael), Stella Yamada (Hayley Kiyoko), and Wendell "Wen" Gifford (Adam Hicks) all meet after ending up in detention for different reasons. Miss Reznick (Tisha Campbell-Martin), the music teacher supervising detention, leaves to argue with the principal Mr. Brenigen (Christopher McDonald) about his decision to move all extracurricular activities to the basement to make room for a new gymnasium. The five then tap out a beat and play instruments, and Olivia sings "Turn Up the Music." Miss Reznick returns and says that they would make a great band, and encourages then to enter a music competition called "Rising Star," in which a popular band, Mudslide Crush, planned to enter.
The following day, Stella sends a text message to the members stating: Fluke or Destiny? We need to talk. The group agrees to chat at Dante's pizza where Stella reveals she signed the band up for Rising Star and the Halloween Bash.
The band forms with Olivia as lead vocalist, Stella as lead guitarist, Mo as bass guitarist, Wen as keyboardist, and Charlie as drummer. At school, Olivia gets cornered by Ray Beech (Chris Brochu), lead singer of Mudslide Crush. Stella spits lemonade on Ray in defense. Ray refers to Stella as "lemonade mouth," giving the band its name. The band later discovers the lemonade machine is being removed.
When Mo sees her boyfriend Scott Picket (Nick Roux), the guitarist of Mudslide Crush, flirting with another girl, Jules (Caitlin Ribbans) she leaves him. At the Halloween Bash, Lemonade Mouth performs "Determinate." After the performance, Stella makes a speech opposing Brenigen's decisions and encouraging self-expression to the supportive crowd. Angered, Principal Brenigen forbids them from playing at school. The next day, the band sees posters and banners all around the school supporting Lemonade Mouth, raising their spirits. Mo sings "She's so Gone" at the regular gig they have. They also discover that "Determinate" is being played on the local radio. Shortly after, however, things go downhill: Mo gets sick, Charlie breaks his fingers, Wen injures his eye, and Olivia loses her voice.
Stella calls the band to the school, where she is protesting the removal of the lemonade machine. The group gets into a heated argument with the men removing the lemonade machine. Police arrive and they are brought to a holding cell to wait for their parents. They slowly come together singing "Turn up the Music." The band agrees to perform at Rising Star, after contemplating quitting.
At Rising Star, Mudslide Crush performs "Don't Ya Wish U Were Us." Lemonade Mouth unsuccessfully performs "Determinate." The audience begins to sing "Determinate" in support of the band. Fed up with Ray, Scott leaves Mudslide Crush and joins Lemonade Mouth. Mo and Scott get back together, Charlie begins talking with a girl who likes him, Stella and her mother become close again, and Wen accepts his new stepmother.
At Wen's father's wedding, Stella recognizes the man sitting next to her as Mel, the owner of the lemonade company. He donates a music hall to the school, which Mr. Brenigen accepts. Olivia mails the entire story to her father, who is in prison. The standard edition of the film closes with Lemonade Mouth performing "Breakthrough" at Madison Square Garden, with Scott as their new additional guitarist. The extended edition includes an interview with Moxie Morris on "All Things Musical", in which Mo and Scott's relationship is nearly exposed by Moxie in front of Mo's father, but is stopped by Olivia, who says that she and Wen are dating. The band performs "Livin On A High Wire".Bridgit Mendler as Olivia White, the lead singer of the band
Adam Hicks as Wendell "Wen" Gifford, the pianist and also a rapper of the band
Hayley Kiyoko as Stella Yamada, the lead guitarist of the band
Naomi Scott as Mohini "Mo" Banjaree, the bassist of the band
Blake Michael as Charles "Charlie" Delgado, the drummer of the band
Nick Roux as Scott Pickett, Mo's boyfriend
Chris Brochu as Ray Beech
Tisha Campbell-Martin as Miss Jenny Reznick
Christopher McDonald as Principal Stanley Brenigan
Scott Takeda as Mr. Yamada
Ariana Smythe as Sydney
Judith Rane as Brenda
Isaac Kappy as Mel
Ryan Montano as Tommy Delgado
Lauren Poole as Moxie Morris
Bob Jesser as Mr. Gifford
Leedy Corbin as Georgie Gifford
Lance Capaldi as Ticket Taker
Shishir Kurup as Mr. Banjaree, Mo's dad
Author Mark Peter Hughes makes a cameo appearance as an extra dressed as a bee at the Halloween Bash.
The movie was filmed in Albuquerque, New Mexico. The names of eight characters in the book were changed for the film: the character of "Olivia Whitehead" was changed to "Olivia White," "Wendel Gifford" was changed to "Wendell Gifford," "Stella Penn" was changed to "Stella Yamada," "Mohini Banerjee" was changed to "Mohini Banjaree," and "Charlie Hirsh" was changed to "Charlie Delgado." Casting was announced in August 2010.
Family-oriented reviewers at Common Sense Media praised the film for its themes of honesty, empowerment, overcoming adversity, self-expression, standing up for what one believes in, and for its emphasis on the importance of the arts and of friendship and family. Other reviews were not so kind, with some critics claiming that Lemonade Mouth is a "typically innocuous Disney Channel flick" that is a "hopelessly dumbed-down endeavor." The film holds an 6.7 rating, making "Fair" (based on 17 votes) on TV.com.
Lemonade Mouth was watched by 5.7 million viewers on its premiere night. ranking as the No. 1 TV Telecast among Kids 7–11 (2.3 million/9.4 rating) and Teens (2.1 million/8.5 rating), and cable's No. 1 original movie of 2011 among Total Viewers. With DVR viewing included, its total was 7.1 million viewers.
A local premiere was held in the author Mark Peter Hughes's town of Wayland, Massachusetts. It was broadcast live by the town public access station, WayCAM.TV, by local students. The premiere broadcast was directed and produced by technical student Jonah Camiel.
The cast from the film have performed on The View, Good Morning America, So Random! and UK's Daybreak.
The movie features ten original songs written by Aris Archontis, Maria Christensen, Ali Dee, Andy Dodd, Tom Leonard, Jeannie Lurie, Niclas Molinder, Chen Neeman, Joacim Persson, Lindy Robbins, Shridhar Solanki, Shane Stevens, Matthew Tishler, Bryan Todd, Reed Vertelney, Adam Watts, and Adam Hicks. Walt Disney Records released the soundtrack on April 12, 2011.
In 2011, the author of Lemonade Mouth said that he had been working on a sequel. Actor Blake Michael has said: "It's all up to the fans, it's in their hands. If people enjoy it and they love it and they want more, they'll get it. I think Disney is just a great organization in general and they're always one step ahead of the game. So you never really know what's gonna happen." On June 15, 2011, it was announced during the 2011 Licensing International Expo that Lemonade Mouth 2 was in the works.
On April 6, 2012, Chris Brochu announced on his Twitter account, that the sequel was no longer going into production. In interviews with Kidzworld Media and BSCKids in May 2012, Bridgit Mendler also confirmed that a sequel would not be produced, noting that "they tried to figure something out for a sequel, but everyone at Disney felt like the movie had completed its story in the first movie."