Visible crew/equipment: When Harry and Marv are making their way across the rope to the tree-house, you can see them dangling in a long shot. It has to be stuntmen because, despite the 12 inch height difference between the characters, they seem to be the same size while hanging there.

Revealing: When Kevin screams from putting on aftershave, the shot cuts to the spider running behind the toilet. You can see white tiny pellets being thrown at the spider from behind. This must have been to make sure it kept moving during the shot.

Deliberate "mistake": Kevin rides down the stairs on his sled and out the door. He originally lined up the sled at the top of the stairs, but it is clear that the stairs lie to the right of the door. His sled went straight down the stairs, therefore making it impossible go straight out the door in one movement as shown.

Continuity: When the family is rushing all over the house because they're late, they show Brooke coming down the stairs and Heather going up the stairs. Then the scene goes to Mitch Murphy and then comes back to the family rushing. The scene shows the same shot of Brooke and Heather going down and up the stairs.

Continuity: When the robber with the beard gets hit in the face with an iron, the iron hits him on the face, and leaves a mark slanted to the right. It also leaves a mark on his nose. When the two robbers are talking after they have been tricked and before Kevin puts the spider on one of the robbers, the iron mark is vertical and there is no mark on the nose anymore.

Continuity: When Harry is telling Marv when the Christmas lights on the house are going off, right before they are going to rob the house, they show the dashboard of the van. There is nothing on it. When they pull into the driveway, there's paper and other things on the dashboard.

Continuity: Right after Marv loses his shoes on the tar covered stairs he goes back outside to go in the window. When he's running in the snow you can see that he is wearing little pink booties so his feet don't get cold.  When he is getting into the police car at the end, you see a short shot of his feet when he's almost in and you can clearly see he has black boots back on.

Factual error: In the scene where John Candy and Catherine O'Hara are in the van and John Candy plays the clarinet, he never changes the positions of his fingers, but he plays a different note.

Plot hole: When Kevin's family arrives late to the airport on their way to Paris, the person at the gate doesn't check their tickets and their seats are waiting for them during the one of the heaviest travel days of the year. Normally, stand-by's would have filled up those seats.

Continuity: In the scene where the robber is breaking into the basement, the steps and concrete by the door are icy. However, when the camera angle changes and it shows the same scene looking out of the basement, there is no ice at all.

Continuity: In the scene where Kevin goes flying into his treehouse and breaks out the wood, the amount of wood missing changes from one scene to the next.

Continuity: The morning that Kevin wakes up looking for his family, his hair changes in each scene and stands up straighter on top.

Deliberate "mistake": In the scene where Kevin swipes the toothbrush from the drugstore, he slides across a skating rink on his knees while being chased by the cop. Ice is slippery, but not THAT slippery (especially when it's been skated on). Kevin would have only slid a few feet before coming to a stop.

Continuity: After Kevin has been out of the house and said, "I'm not afraid anymore", it was night, but when his mom calls from Paris and they send a policeman to their house, it is broad daylight and Kevin is still under the bed cover.

Continuity: In the supermarket when Kevin puts the groceries on the conveyor belt, he sets the tissue paper standing up. The next shot of Kevin shows the tissue on its side and farther back, the next shot it's back to its original position.

Continuity: When Kevin is preening himself in the mirror while giving a running commentary of his washing habits, you can see the shower gel (facing forward), aftershave and deodorant to his left by the sink. When it cuts to a close shot, a bottle of fragrance has mysteriously appeared by these items and the shower gel is facing away from Kevin.

Continuity: When the 2 burglars are breaking into the McAllister home, the tall burglar gets hit square in the face by an iron...he has iron marks on his forehead and cheeks but not his nose...how could the iron not hit his nose?

Continuity: When Harry slips and somersaults down the Mccallister's iced front door steps for the second time, his hat falls off at the base of the stairs while he's tumbling, yet in the subsequent shot showing Harry, he is wearing his hat again.

Continuity: Harry and Marv both get hit with the paint containers on the stairs. Look at the front doorway when Marv gets hit. The cord (from the hot implement attached on the doorknob) is in an 'S' shape and lots of micro machines litter the doorway. Harry then gets hit. When he gets up to go up the stairs after Kevin, the cord has moved and the micro machines are well clear of the doorway.