Continuity mistake: When Gabriella and Troy are up in the treehouse, the three flower hair barrettes on Gabriella's right side form a triangle. Depending on the angle of the shot, the 'triangle' of flowers are formed with one flower at the top and two lower, or two flowers at the top with one lower flower.
Continuity mistake: In the scene where Troy and Gabriella are sitting on the edge of the treehouse, Troy's hands on his leg continue to move up and down suddenly, between shots.
Continuity mistake: Just as Gabriella and Troy walk into Gabriella's backyard, they put their belongings down on the table, with an Adirondack chair beside it and the second Adirondack farther away from the table, mostly out of frame. Next shot, when they sit on the hammock, that second Adirondack which was out of frame has moved forward, so the end of its arm rest is level with the table's corner. When Mrs. Montez comes out it's back to the way it was in the first shot. (00:37:20)
Continuity mistake: During the musical number "Just Wanna Be With You," Troy jumps onto the railing and hangs off of it with one hand when he sings the line "no matter where life takes us." The paint on the railing is obviously still wet, because Jimmie can be seen painting it. However, in all subsequent shots, there is no white paint on Troy's hand until he climbs over the railing later in the song.
Continuity mistake: Just before "I Want It All" in the cafeteria, Sharpay pushes Ryan's lunch tray away, then pushes it again some more off to her left. When the shot faces Ryan, the tray is back near Sharpay, but when the next shot faces Sharpay the tray has moved even farther off to her left again. She does not touch the tray between these shots.
Continuity mistake: When Troy and Gabriella are dancing on the rooftop, the potted trees and hanging potted plants are swaying in the wind in some shots but are motionless in other shots.
Continuity mistake: When Gabriella speaks out to everyone in front of the piano, to get them to agree to do the musical, in the first shot her hair is over both of her shoulders, then it is pulled back behind her right shoulder. In the next shot it is hanging in front of both her shoulders again.
Continuity mistake: During the rehearsal of "Just Wanna Be With You", Jimmie leaves the cup of paint and paintbrush beside the railing. Not only does the cup of paint move (note rail post and pickets) in following shots, but after Gabriella dabs paint on Troy, the paint cup just vanishes, as well as the paintbrush Gabriella dropped. (00:52:05)
Continuity mistake: When Troy and Gabriella are rehearsing "Just Wanna Be With you," Jimmie is seen painting in the background. In the first shot, Jimmie is crouching and gradually stands up. In the next shot, Jimmie is crouching again. (00:50:45)