At the end of the song "She's So Gone" at Dante's Pizza, Olivia and Stella switch places through three different frames. First Olivia is on Mo's right, then left, and when they pull back for the whole band Olivia is on her right again.
During Stella's speech at the Halloween Bash, Olivia can be seen in the background standing still with her guitar. At the end of Stella's speech, Olivia is in the process of putting on her guitar.
At the end of the movie, during the conference, Stella has her legs crossed and uncrossed alternately.
Two figures are visible behind the pillar when the band is playing on the terrace after the swim in the pool scene. However, looking closer at the boys, they are Stella's two younger brothers, not crew members.
The first preview of Lemonade Mouth in 'The Road Runner Gazette' was just about four lines. The same words were repeated over and over again to fill up the page.
When Stella is coming out of the principal's office and heads to the elevator, she passes a group of cheerleaders. They start cheering but none of them are moving their mouths.
When they are singing by the pool after Olivia's cat passes away, a man in a plaid shirt holding a boom microphone can be seen in full as the camera pans to the band playing on the steps.
When the kids are outside by the truck that will take away the vending machine, as rain begins to fall, the shadow of the rain rig used by special effects is visible in the background.
When the band sings "Determinate" at the "Halloween Bash", you can see the camera man moving on the bottom of the screen from the right to left then back from the left to right during the beginning of the song.
During the rival band's performance at a warehouse, you could see the cameraman and a crew member pushing the dolly cart in the shot.
When their song is played on the radio, Wen calls Stella to tell her to tune her radio to WRIZ. Call letters in Arizona and other Western states begin with "K." "W" is the Eastern call letter. This was probably a hold-over from the book, which took place in Rhode Island.