Continuity mistake: In one scene where the dad is leaving for work, he sees a dog and in that shot you see his mail truck and the door is open. Then you go to a close-up of the dog and when he runs to his mail truck the door is now shut.
Continuity mistake: When Mac and Sydney get caught by the girls and Mary-Kate goes to put nailpolish on Mac, she holds up red nailpolish. When it shows his nails, there is no red nailpolish on.
Continuity mistake: When Ashley steps in to compete in the surfing contest, as she is surfing her hair is soaked and dripping wet, but when she emerges her hair is mostly dry.
Continuity mistake: When the girls are on Victoria's boat at the party, in one shot, Abby is wearing the diamond necklace, but in the next, it disappears, and it keeps doing that throughout the scene.
Continuity mistake: When Ashley and Mary-Kate are being tested by the people at their school, one of the Olsen twins has to eat a large spoonful of Vegemite. It is definitely not Vegemite. It is too light in colour and too soft, it is almost definitely chocolate.
Continuity mistake: When Mary-Kate and Ashley are near the museum, the camera shows the museum from the outside. You see one of the thieves start to run out. Then it goes inside the museum and the guys are stealing the jewel. Then it shows the museum from the outside again and it shows the guy running out just like he had before.
Continuity mistake: When they have a "break" and have a party, they throw confetti up in the air. When they come back to reality and hear that they are to be moved to another location, one of them still has confetti on their shoulder even though it only existed in their "fantasy".