Production was nearly halted towards the end of shooting due to Christopher Pettiet's drug addiction, which was just starting to get out of control. The producers wound up cutting a few of his scenes to keep the film on schedule.
Before Sue Ellen stomps out of Kenny's room, she yells, "When are you going to start helping me, you lazy little prick?" but director Stephen Herek decided he didn't want to take any chances of the movie receiving an R rating so he had the scene fixed for Sue Ellen to call Kenny a lazy little "punk" instead.
When the movie was released on video, there was a contest where participants would answer a number of questions about the movie related to movie trivia as well as ratings of various actors' performances. The winner, whose answers matched up the best with an official set, would win the babysitter's car (the one stolen by the drag queens).
Christina Applegate gained nearly 10 pounds in order to play a 17-year-old teenager. She lost all of that weight soon after filming ended to continue her role on the TV series "Married... with Children" for it's fifth season.
In one of the earlier script drafts the babysitter's death was supposed to be a more elaborate storyline: the Crandell children were all suspects, and they all had their reasons to kill her. Although certain scenes were scaled down, elements of their motives remain in the final cut of the film: Walter having to do a book report, Melissa forced to wear a dress, Zack losing Cynthia.