The scene in which all characters sit in a circle on the floor in the library and tell stories about why they were in detention was not scripted. Writer and director John Hughes told them all to ad-lib.

When the kids are running through the halls of the school, they run past a window that seemingly reveals it is dark outside. In actual fact, they are running past doors leading into classrooms, in which the lights are turned off because it is the weekend.

Opens with the following which then explodes from the screen. "And these children that you spit on as they try to change their worlds; are immune to your consultations, they are quite aware of what they are going through." -David Bowie

When they sneak out of the library, there is a scene where Dick is at the vending machine getting some candy. He loses his money and starts kicking the machine. Every one has to run by this door one at a time to get where they are going. They all run by just missing being noticed. Ally Sheedy however slowly walks by stops and stares at Dick kicking the machine then slowly walks past unnoticed. Molly Ringwald then says "She's nuts but she's cool"

Edited into The Breakfast Club: Deleted Scenes (2018)