Continuity mistake: Charlie Brown's Christmas tree is never the same. When we first see it, it has three branches. Later, when he's carrying it, it has four branches. Then, when he tries to decorate it and it flops over, it has six branches.
Continuity mistake: In the same scene at Lucy's Psychiatric Help stand in which the Doctor is both "in" and "real in", the word "Doctor" also moves around on the sign at one point. (00:04:40)
Continuity mistake: The string of Christmas lights which the Peanuts gang remove from Snoopy's doghouse are flashing multi-colored lights. After they "re-do" the little tree, at first the string of lights is not on the tree. In following shots, the string of lights appear, but they are now steady-on yellow lights. (00:23:45)
Continuity mistake: When Charlie Brown is talking to Lucy at her Psychiatrist booth, the sign says "The Doctor is Real In" or "The Doctor is In" depending on the viewing angle.
Continuity mistake: This one goes by fast. At the beginning of the show, the skating children are seen all linked together in an extreme close-up. In a long-shot immediately after that, the last few children are shown just arriving to link up. (00:02:05)
Continuity mistake: When Linus gives his biblical recital on the true meaning of Christmas, there is a United States flag on stage at the top of the stairs (viewer's right). When the shot changes to a side view of Linus, the flag is not there. (00:20:45 - 00:21:30)
Continuity mistake: When Snoopy first decorates his doghouse, there are trees and a wooden fence near the doghouse. Later, when the Peanuts gang remove the decorations from the doghouse, neither the trees nor the fence are there anymore. (00:07:15 - 00:24:10)
Revealing mistake: When Charlie Brown stops to watch Snoopy sitting atop the doghouse, eating dog bones, the pile of bones never goes down even though Snoopy takes from the pile three times. (00:03:25)
Continuity mistake: When Charlie Brown and Linus leave the auditorium to go and get a Christmas tree, they are shown exiting the same yellow building which they had exited from at the beginning of the show. Later, when Charlie Brown exits from the same auditorium, bringing the little tree with him, he exits from a red brick building. (00:16:15 - 00:22:10)
Character mistake: Lucy refers to fear of cats as "ailurophasia", which is incorrect; fear of cats is called "ailurophobia."
Continuity mistake: The planks that hold up the sign of Lucy's psychiatric booth are red, but when Lucy suggests that Charlie Brown has hypengyophobia and it cuts to Charlie Brown, the left plank is orange. (00:05:22)
Continuity mistake: When Lucy talks to Charlie Brown at her psychiatric booth, there is a money jar on the counter. After Charlie Brown screams, "That's it!" and Lucy falls over, the money jar is gone. (00:05:53)
Other mistake: Throughout the scene where Lucy is at her psychiatric booth, her body clips through it in many shots. (00:04:36 - 00:05:26)
Continuity mistake: While Schroeder is playing piano, Snoopy abruptly pops in out of nowhere, in the middle of the frame, and starts dancing.
