Other mistake: When Richard is at the babysitters he empties an Erector set can but it contains Lincoln Logs. Erector sets came in metal boxes, not cans like Lincoln Logs.
Continuity mistake: During most of the film (leading up to Clarissa's party), there are folding oak-colored wooden chairs arranged against the bookshelves in the foyer, ostensibly to be used at the party. However, during the scene where Laura Brown meets Clarissa and the apartment is arranged for the party, the only chairs utilized are non-folding white chairs (and the wooden chairs are gone).
Continuity mistake: When Laura Brown's son and husband are eating breakfast, watch her son's bowl of cereal (I think it's corn flakes with sliced bananas). As the scene progresses, the amount of corn flakes in the bowl grows and lessens, banana slices disappear and reappear, and the spoon changes positions several times.
Continuity mistake: The scene where Virgina sits down on the trunk where her niece has bedded the dead bird on a leaf there some inconsistencies. Virginia is holding four or five roses in the hand. She breaks one blossom off and puts it down on the leaf (we don't see where exactly, though). Then the camera cuts to her upper body, and she is apparently not doing anything with her hands, but in the next, wider shot only one rose is left in her hand. Then, in a close up of the bird we see no roses at all. Finally, in the last shot of the scene she is seen putting three blossoms around the bird which were not in her hands when we saw them last.
Continuity mistake: When Mr. and Mrs. Woolf have their heated discussion at the train station, the bangs of his hair constantly change between three different looks: all messed up, messed up with one separate strand hanging down and neat and parted over to the left.
Continuity mistake: When Virginia Woolf is at the train station trying to go to London, the clock at the station reads 5:20. It progresses naturally throughout the scene as if care were taken to make it seem natural. However, when her husband arrives, his wrist watch is in clear view and reads 9:30.