- Completely Different Title: The film was released as Lethal Attraction in Europe.
- Contractual Purity: Winona Ryder was still known for family-friendly roles at the time, and her agent begged her not to star in the film, fearing her career would be over. The same week Winona received the script, a schoolmate of hers committed suicide, which inspired her to do the film in spite of potential career damage.
- Corpsing: Shannen Doherty had been raised in a very conservative family and was not used to so much swearing. She can be seen corpsing over her own line "Veronica, why are you pulling my dick?"
- Dawson Casting: The majority of the students were played by actors in their early twenties. This is averted by Veronica and Heather Duke—Winona Ryder had her sixteenth birthday on set, complete with cake, and Shannen Doherty was 17 when the film was released. Christian Slater just about gets by, being nineteen at the time. Most of the extras are in their late 30s (look close). According to Word of God on the DVD Commentary, having high school extras in their late 30s was a Running Gag for New Line Cinema.
- Executive Veto:
The best thing, though, in that museum was that everything always stayed right where it was. Nobody'd move. You could go there a hundred times, and that Eskimo would still be just finished catching those two fish, the birds would still be on their way south, the deers would still be drinking out of that water hole, with their pretty antlers and their pretty, skinny legs, and that squaw with the naked bosom would still be weaving that same blanket. Nobody'd be different. The only thing that would be different would be you.
- The original ending had Veronica take J.D.'s bomb and blow up herself and everyone in school, followed by a surreal sequence where everyone who died is shown in the afterlife at a prom, where everyone — regardless of what clique they were in when they were living, if they were in a clique at all — gets along. This was regarded as "too dark" by executives and it was changed to one where Veronica rejects J.D.'s ideals and J.D. kills himself with the bomb..
- Executives also changed Heather's posthumous underlined copy of Catcher In The Rye to Moby-Dick, due to the notorious real-life killers associated with Catcher. (And due to Salinger's refusal to relinquish the rights). The word "Eskimo" does not appear in Moby Dick for Heather to have underlined (though "Esqimaux" appearsnote ), whereas Catcher has the following section about the Natural History Museum:
- The "Snappy Snack Shack" was supposed to be a 7-11 but the execs at the chain didn't want to be associated with the film.
- Life Imitates Art: As in the movie, in 2006-2008, a lot of teenagers in Bridgend, Wales decided to commit suicide on Bebo for no reason other than the fact that everyone else was doing it.
- Mean Character, Nice Actor : On the DVD commentary, people comment that Kim Walker is nothing like her on-screen character.
- Romance on the Set: Christian Slater and Kim Walker were dating at the time. He also briefly went out with Winona Ryder, which she said lasted only a week.
- Stillborn Franchise: Writer Daniel Waters claims he had an idea for a Denser and Wackier sequel where Veronica would end up working for an evil senator also called Heather - played by Meryl Streep. The film would end with Veronica assassinating the president and getting away with it. Winona Ryder apparently loved the idea, but it never got made. Another suggested idea for the sequel would have JD being revealed to have been a CIA agent - and the CIA blackmail Veronica into assassinating the president.
- What Could Have Been:
- The leads were almost played by Jennifer Connelly and Brad Pitt. Connelly turned down the role to audition for Say Anything... (which she lost out to Ione Skye) and Pitt was turned down for seeming "too nice". Heather Graham was also considered for Heather Chandler, until her mother vetoed the script due to the dark subject matter (she's since become estranged from her parents over their disapproval of some of her roles). Drew Barrymore auditioned too.
- According to Word of God on the DVD commentary, New Line Cinema also wanted Justine Bateman for Veronica.
- Jim Carrey, Judd Nelson and Jason Bateman were considered for J.D.
- Daniel Waters originally wanted Stanley Kubrick to direct, citing that "He's the only one that can get away with a 3 hour movie."
- A script for a TV version was pitched to the then-fledgling Fox Network. They had to decide between a TV adaptation of Heathers and some teen show called "Beverly Hills High" (though you might recognize it by its more popular name: Beverly Hills 90210). Shannen Doherty of course starred in both.
- Shannen Doherty auditioned for Veronica, but Winona Ryder had already been cast. Keen to have her on the film, they offered her Heather Chandler. Shannen instead preferred to play Heather Duke.
- An early draft of the script had a scene where Veronica would try to test the blanks out on her cat, but JD would stop her by saying "they don't work on small animals"
- An alternate ending had Veronica getting stabbed by Martha Dumptruck, who would scream "fuck you, Heather!" - and Veronica's Famous Last Words would be "My name's not Heather!"
- Cut Song:
- A reprise of "Fight for Me" and many from the Los Angeles production.
- An early reprise of Candy Store that had the exact same music, but the only lyrics were "Great pate, Mom."
- Playing Against Type: At least two of J.D.'s actors so far have indulged in this. Ryan McCartan is mainly known for playing a Lovable Jock on Liv and Maddie, while Thomas Sanders is known for his sweet, charming Nice Guy personality in all his works.