Continuity mistake: In the scene where Lizzie's parents are seeing her off for her trip to Rome, she first walks away from her family after exchanging hugs and the legs of her pants are rolled up. She then turns around and walks back for a second hug with her mother and when she turns around and walks away from the family a second time, her pants are no longer rolled up.
Continuity mistake: In the scene when Lizzie and Paolo stop to have a look at the view, Lizzie's hair is braided. In the next scene, when they go to the designer's place, her hair is tied up. If her hair was braided, she wouldn't have been able to tie her hair up that easily. In the next scene when she did her cartwheel outside and said "Good-Bye Lizzie McGuire, Hello Fabulous" her hair is braided once again.
Continuity mistake: When Paolo and Lizzie are in the rehearsal hall and Paolo is teaching Lizzie to dance, he is sitting of a chair with a remote control in his left hand, giving her directions. He then stands up to show her a move. He puts the remote down on the chair and stands up. During the move that he shows her, the remote reappears in his left hand. (01:05:15)
Continuity mistake: At the end of the movie, you have Lizzie McGuire singing in front of thousands of people. In one shot you can see all the fans as if they were standing on the floor all the way to the walls on the opposite side of the Colliseum, but in the next shot it looks like it is a totally different seating plan, as the seats are going up.
Continuity mistake: In the scene where the group are waiting in the lobby for their room assignments, Lizzie's hair has noticeable kinks where her pig tails were for the flight but when she's upstairs her hair is perfect and shiny and straight. She wouldn't have had time to change it walking upstairs.
Continuity mistake: In the sceen where Kate first appears in the airport and says "How many Lizzies does it take to screw in a lightbulb..." there is a parked airplane visible in the window behind her. After a quick cut to Lizzie the scene cuts immediately back to Kate and the airplane is gone. Airplanes don't leave the gate that quickly.
Continuity mistake: If you pay close attention, Paolo's accent doesn't always stay the same. At most times, there is a clear Italian accent, but at others, an American accent can be heard.