Revealing mistake: When Troy says "I'll sing with her," Ms. Darbus turns around "in response" to his voice before he even says anything.
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.
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.) (00:33:40 - 00:35:40)
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. (00:07:50 - 00:37:55)
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'. (01:00:55)
Continuity mistake: In the locker room scene where Troy walks in and his teammates confront him, Zeke describes the MVP in his picture, sits down, and puts the picture on the table twice.
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).
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. (00:25:00 - 00:34:50)
Audio problem: In "What I've Been Looking For", when Sharpay sings the last verse the first time around, listen closely as Ryan takes away the microphone. Her voice remains the same volume, and does not get any quieter as Ryan pulls away the microphone.
Continuity mistake: During the "Status Quo" number, we never see Gabriella walking through the cafeteria in the wideshot, after she talks to Taylor, unless it is a close up shot of her.
Continuity mistake: Near the end of "Start of Something New" when Troy is saying "new" he moves the mic away from his mouth, but you can still hear him saying "new" before he puts it back to his mouth.
Continuity mistake: When Gabriella gets her picture taken on Troy's cellphone, she looks directly at the lens. When Troy looks at the picture, it's an angled shot of Gabriella and she's looking elsewhere.
Revealing mistake: In the final scene "We're All In This Together", when Ryan is getting ready to jump off of the bleachers and be caught by his classmates, you can see Troy motion for Gabriella to move forward into the correct position for the shot.
Continuity mistake: When Kelsi trips over as she walks away from the piano, her composing sheets fall and scatter all over the floor, and by the piano. In the next shot the sheets are now suddenly all close to her so that she can pick them all up in this shot.
Audio problem: When Gabriella is singing "When There Was Me and You", when she sings the line "Like I could Sing Along", notice her mouth doesn't move.