When submitting his script to studios, screenwriter Adam Herz titled it, "Untitled Teenage Sex Comedy That Can Be Made For Under $10 Million That Most Readers Will Probably Hate But I Think You Will Love". It was later changed to "East Great Falls High", then "Great Falls", and finally, "American Pie".
Alyson Hannigan went to her callback audition really having to pee. She ran to the bathroom and her name was called right after she got out. She went in without having calmed down so she read the part really quirky and with an over amount of energy. She credits that to her getting the part.
When Jim was running down the road to get to his house, Jason Biggs got heatstroke. They had to pack his shirt with ice to cool him down while he was running. Afterwards, they rushed him to a doctor. In another incident, while at home Jason Biggs also took too many Zinc supplements and became ill, so Jim was completely written out of the scene where Kevin and Finch are talking to each other while Finch is playing golf.
Was, alongside South Park: Bigger Longer & Uncut (1999), one of two explicit films released on the summer of 1999, with the highest number of reports of underage fans engaging in unsuccessful attempts to gain entrance and watch the film in theaters.
Eugene Levy was told he could improvise much of the dialogue for his character, including the part when flipping through the pornographic magazines with Jim, forcing a noticeably muffled laugh from Jason Biggs with the "giant orgy" line.
Shortly after appearing nude in this film, Shannon Elizabeth went on to do a Playboy spread. After that, she decided to quit appearing nude in films, out of fear of being typecast. She later called her Playboy appearance "one of [her] biggest regrets".
When Eugene Levy auditioned for this film, it's title was "East Great Falls High" and he was already shooting an independent film titled "American Pie". The indie had to change its name to The Secret Life of Girls (1999).
Adam Herz's High School (and the one upon which he based East Great Falls High) was East Grand Rapids High. Yesterdog is the real name of the hot-dog "hang-out spot" for many of the real-life students.
The scene in which Finch's scooter breaks down in front of Dog Years hot dog shop was unplanned. Director's Paul Weitz and Chris Weitz thought the scene was funny so they decided to leave it in the final cut of the film.
The URL for the webcam broadcast that Jim emails (from email@example.com) to his friends is http://22.214.171.124/temp/NadiaVision. (The IP address actually belongs to the Department of Psychology of the Johns Hopkins University in Baltimore, MD.)
The part when Jessica and Vicky are reading the Spanish work and Jessica says, "Is this right, "go away, you stupid bird teacher, I had enough" was an inside joke from writer Adam Herz when he was in high school.
Alyson Hannigan stayed in character after shooting her scenes, as she would annoyed herself by continuing to talk off-camera, like her quirky character Michelle, by ending sentences with a superfluous question mark.
Contrary to popular belief, American Pie (1999) didn't actually invent the term "MILF". A 1995 Usenet post initially used the acronym, pre-dating the movie by four years. However, the film is largely credited as being the one to significantly popularize the term.
In the sequence where you see all the boys working on their skills to get a woman Chris Klein is watching the womens network and has a YM magazine on his lap with Katie Holmes on the cover. Klein and Holmes dated for 5 years and were engaged for 2 of them.
Screenwriter Adam Herz wrote the original screenplay in just six weeks. For research, he watched Porky's and Bachelor Party repeatedly to study the comedy in those high school movies which were, similarly, sex-obsessed.