Continuity mistake: The scene where the elementary school teacher asks his kid what they did that week. After he asks that question and Maizy raises her hand, look at the desk belonging to the girl in the row next to Maizy. It has crayons and other supplies on it. After the teacher calls Maizy's name, the shot goes back to her, showing the girl in the next row's desk completely empty.
Factual error: In the shot where Uncle Buck is in the living room dancing with that woman, the song "Laugh Laugh" by the Beau Brummels is playing. However, the 45 we see spinning on the turntable is not "Laugh Laugh". It is a 45 on the Uni label, and the Beau Brummels' 45s were on the Autumn label.
Continuity mistake: When Buck is on the highway driving to the house and trying to remember the kids' names, we see a white 4x4 travelling the same speed as him but several lanes over. When it cuts to a shot of the rear of Buck's car, there is a small sedan now in the left lane beside him that wasn't there before.
Continuity mistake: In the scene where Cindy and Bob are talking in the kitchen (after getting the news) and the scene of Cindy and Buck talking in the kitchen, several items change dramatically. The coats on the rack change positions and the yellow coat goes from an adult size to a kid size. A drawing on the kitchen wall is removed too.
Continuity mistake: When Miles Russell is unpacking his lunch and asks about a lunch trade, the other kids scatter. The items on the table change when the camera cuts to the overhead shot. Most noticeably a soda can and snack appear in between Miles' food and the bag of Fritos, and the juice box is gone.
Revealing mistake: In the scene where Buck causes all the pots and pans to crash while Tia and her mother are hugging, the final of the "reaction shots" is a close up of the two kids. You can see Amy Madigan squeeze their arms as a cue to make their shocked expressions; prior to this Gaby Hoffman was looking up with a neutral expression on her face.