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.)
Chad Danforth: Have you ever seen Michael Crawford on a cereal box?
Troy Bolton: Who's Michael Crawford?
Chad Danforth: Exactly my point! He was the Phantom of the Opera on Broadway. Now, my mom, she's seen that musical 27 times and she put Michael Crawford's picture in our refrigerator. Not on it, in it. So, my point is if you play basketball, you're gonna end up on a cereal box. If you sing in musicals, you're gonna end up in my mom's refrigerator.
Troy Bolton: Why would she put his picture in her refrigerator?
Chad Danforth: One of her crazy diet ideas! Look, I don't have time to understand the female mind, Troy!