Other mistake: In the end credits, Santa's name in the song title "Santa Claus is Comin' to Town" is misspelled as "Clause."
Factual error: On Christmas morning when the Parker's are opening gifts, several Christmas songs can be heard playing in the background. Several of these were released long after when the movie is set (around 1940), particularly Bing Crosby's performance of "It's Beginning to Look a Lot Like Christmas," which was released in October of 1951.
Revealing mistake: The wind up tank in the toy store window can't possibly be a continual display. Clearly a production assistant wound up and released the tank for the shot. It's not a toy that would be moving with the other display items.
Continuity mistake: The old man throws straw everywhere getting his prize out of the crate, and a lot of it goes on his back. The straw disappears when he climbs out of the crate.
Factual error: During the tongue on the flagpole scene, the police car that pulls up is a '46 or a '47 Chevrolet sedan. If this movie is supposed to take place pre-WWII, that car wouldn't have existed yet.
Continuity mistake: In the kitchen, after the father comes in to get warm water for his car, the 2 boxes of soap powder move from the left side of the sink to a wall shelf on the right.
Factual error: Early in the film, while the kids are looking at the toys in the Higbee's store window, two uniformed soldiers are visible right behind the kids. The female soldier is wearing sergeant stripes on her sleeves, but the braid on her garrison cap is gold - a color reserved for commissioned officers.
Visible crew/equipment: During the parade, the camera moves in and back a couple of times and the operator's shadow is visible left screen. This is really obvious after the Wizard of Oz characters walk by.
Other mistake: When Ralphie has the fantasy about going blind, watch the Old Man when he asks how they could do what they did. He has his hand over his mouth, and he's trying to keep from laughing.
Continuity mistake: In the very beginning the camera is panning, showing Ralph's house next to an empty lot and continues past, showing that across the street is a corner house with hedges. So Ralph's front window would be staring up a street and a line of hedges running up the street. When his father wins the award, the neighbors have their backs to the hedges with the large white house in back of them. This would have them staring across the other street, not at Ralph's house.
Suggested correction: This is wrong. The hedge runs both up 11th St. (Cleveland St.) and Rowley Ave. You can tell this is the correct shot, which includes the side of the house (window and porch) behind the old man.
Factual error: In the beginning of the movie, when they are in front of Higbees, there is an RTA sign on the building in the background. RTA in Cleveland did not exist until around 1975.