Continuity mistake: When Troy tells Chad that he wants to catch up on some homework and then heads to the audition, he's wearing jeans with thick decorative white stitching above his right pocket (viewer's left). However, when Troy raises his hand and volunteers to sing with Gabriella, he is wearing different jeans - the decorative stitching above the pocket is gone.
Continuity mistake: After Ryan and Sharpay's initial audition, when Ryan tells the girl not to be discouraged because the theater needs fans, the blue janitor's cart is visible in the doorway. When Troy and Gabriella help Kelsi pick up the sheet music, the janitor's cart has vanished from that doorway, but when Ms. Darbus comes back to tell Troy and Gabriella about the call-backs, the janitor's cart has reappeared. (There are two doorways that have green exit signs overhead, at the back wall opposite the stage. Troy leaves the cart at the right doorway.)
Continuity mistake: When Gabriella and Taylor walk through the cafeteria, Sharpay starts walking across the balcony to the stairs, cut to wideshot of the cafeteria and she is back at the center of the balcony with Ryan, motionless, but when it cuts to the next shot she and Ryan are already halfway down the stairs.
Factual error: In the scene where Taylor is trying to prove to Gabriella that Troy is a dumb jock who doesn't care about her, Troy is in the locker room with his friends. Troy's friends are recording Troy on a camera attached to a PC, and the image is seen on Taylor's PC. The message on Taylor's PC says an incorrectly spelled 'Recieving WiFi Signal' instead of 'Receiving'.
Continuity mistake: On the first day back after vacation, the exterior of the school is shown at 7:50 AM (wall clock over doors), with the sun's long shadows being cast facing away from the school. The day after Ms. Darbus overheard Troy and Gabriella singing with Kelsi, there is a voice-over of Sharpay screaming, "Callback!" just as the exterior of the school is shown. The clock reads 3:30, and the sun's long shadows are being cast facing towards the school, but we know that it's not even lunchtime yet.
Continuity mistake: During the speech which the basketball team gives to Troy, we have shots altering between Troy and Chad. When we see Chad, the two guys behind him are standing basically next to each other. When the scene cuts to Troy, the same two guys are now much farther apart (the right one of the two would be blocked by Troy if they stood as close together as in the previous shot).
Add timeChristoph Galuschka
Continuity mistake: When Troy tries to ditch Chad to go to the musical audition, he is wearing a belt (as seen when he is going down the school stairs) and white tennis shoes (as seen when he is almost caught by his dad when he rests against the side of the building). However when he makes it to the audition he is now wearing navy blue tennis shoes and no longer wearing a belt (as seen when he "volunteers" to sing with Gabriella).
Continuity mistake: In the homeroom scene, Ms. Darbus says "Mr. Bolton, I see that your phone was involved so I will see you in detention." and we see a close-up of Troy with both of his hands resting on his cell phone, with one hand ready to close the phone. The camera angle zooms out, and, instead, we see one hand resting on his lap and one hand holding the phone.
Continuity mistake: When the cheese fries land on Sharpay, they are all standing right beside the staircase (there are three levels of ledge at the base of the staircase), with Jason and others on the ledge by the banister. Then Sharpay screams. Next shot is of Martha standing atop her table, with the staircase and ledges visible behind them, as they all look to the right, as if Sharpay is farther off in the cafeteria. Problem is that Sharpay, Ryan, Jason, and all the others have vanished, though they all should be right beside that staircase behind Martha's table.
Continuity mistake: Troy and other members of the basketball team say that the big basketball game is in 2 weeks, and the scholastic decathlon members say that their championship is in 1 week, but near the end of the movie their championships are on the same day. We know Sharpay couldn't have changed it because all she asked to be changed was the call back date.
Other mistake: When Sharpay is looking for Gabriella in the girls bathroom, she walks past where Gabriella is hiding behind the wall. It is also shown that there is no other room behind that wall. When Sharpay turns around to walk back out, it is impossible that Gabriella couldn't have been seen by Sharpay as she would have been in direct line with her vision.