Here is some well known and not so well known trivia about TBC :

• The Library was actually a set constructed in the Maine North High School gym
• The movie was filmed at Maine North High School, which is now an Illinois State Police Station!.
• The football oval used at the end of the movie is located behind Glenbrook North High School.
• There is no suburb called Shermer, nor is there a Shermer High School. The name Shermer comes from a street name (Shermer Road) which is where Glenbrook North High School is located..
• The whistling marching tune in the movie is from the movie The Bridge On the River Kwai
• According to Anthony Michael Hall, Judd Nelson was actually the one to coin the phrase Neo-Maxi-Zoomdweebie
• Brians real life mother and sister play his mother and sister in the film.
• Emilio Estevez was originally going to play Bender, but Hughes couldn't find someone to play Andrew Clark so Emilio agreed to play Clark.
• Ally Sheedy was originally cast as Claire.

• Set in the fictional town of Shermer, IL, but actually filmed in Northbrook, IL. The zip code 60062 is the zip code for Northbrook, which was originally called Shermerville. The main north-south road through town is Shermer Road.

• Director John Hughes insisted that the entire cast and crew eat their meals on location in the Maine North High School cafeteria.

• The joke that Bender tells but never finishes (while crawling through the ceiling) actually has no punchline. According to Judd Nelson, he ad-libbed the line. Originally, he was supposed to tell a joke that would end when he came back into the library and said, "Forgot my pencil", but no one could come up with a joke for that punchline.

• Director John Hughes actually attended Glenbrook North High School, one of the schools where the movie was filmed.

• It was originally suggested that there would be several sequels to the Breakfast Club, occurring every ten years, in which the Breakfast Club would get back together.

• Most teenage movies that John Hughes has written are also take place in Shermer Illinois and involve a Shermer High School. Weird Science, written by Hughes and also starring Anthony Michael Hall, also takes place in Shermer.

• The theme song, "Don't You (Forget About Me)", was written for the film by Keith Forsey. It was a number one hit for Simple Minds, and both Billy Idol and Bryan Ferry turned down offers to record it first (although in 2001, Billy Idol recorded Don't You (Forget About Me) as a bonus track for his Greatest Hits album).

• The film's title comes from the nickname invented by students and staff for detention at Glenbrook North High School when John Hughes was a student there. Thus, those who were sent to detention were designated members of "The Breakfast Club".