Continuity mistake: We see a close up of Gabriella slipping in some milk, but in the wide shots there is no milk or carton on the floor.
Continuity mistake: When Troy's mom tells Troy to get ready for the party, his dad gives him the basketball. In the next shot his dad is still holding the ball.
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.