Continuity mistake: The levels of soup in people's bowls change during the dinner scene at the beginning.
Continuity mistake: When Esther comes down the side stairway to attend the party for her brother Lon, the grandfather clock is seen merrily ticking away. Yet when the camera angle changes to show her coming down the main stairway, the clock's pendulum is at a standstill.
Factual error: There are mountains in the background in several of the scenes, but there aren't actually any mountains in or near St Louis.
Other mistake: At the beginning of the Halloween sequence Tootie and Agnes are in their bedroom on the 3rd storey. That same bedroom is across the hall from the bathroom on the 2nd floor in the Christmas sequence. Also when Grandpa looks out his window to see Esther returning from tennis he's looking out a window that would be looking to the side and back yard, not toward the street in front of the house.
Continuity mistake: When Rose and Esther are sitting on the porch watching John Truitt (near the beginning), Esther is sitting very close to the ivy plant and in a close up she is holding one of the flowers, but in the next shot she isn't holding one and is sitting further away. (00:07:10)