1. The movie is based on a book of the same title by Amanda Brown.
2. The book takes inspiration from the author’s personal experiences at Stanford Law School in the ’90s. The character of Elle Woods is somewhat based on Brown herself, who was also a smart blonde student from a California university who got into a prestigious law school.
3. The movie itself was meant to be set in Stanford, but the university administration disapproved so the location was changed to Harvard.
4. Most of the movie was not filmed at Harvard, and instead took place around LA, including at the California Institute of Technology and the University of Southern California.
5. While at Stanford, Brown wrote letters to her friends on pink paper, with a pink furry pen, “lampooning her classmates”. These letters became the basis of the book.
6. Brown said “I was sitting in tort class when the novel popped into my head, I wanted to do a parody of law school.”
7. The character Enid Wexler’s line about changing “semester” to “ovester” was based on an actual discussion at a women’s society meeting Brown attended at Stanford.
8. Reese Witherspoon was a top student and also attended Stanford University, majoring in English literature. She dropped out after a year to pursue an acting career.
9. To prepare for playing the part of Elle Woods, Witherspoon visited sorority girls at the University of Southern California, attending meetings and having dinner with them.
10. She also visited Loyola Law School in LA and sat in on some classes.
11. To get the "California girl" mannerisms right, the Witherspoon spent time in Beverly Hills observing the women who lived there.
12. Witherspoon chose to keep the 60 outfits her character wore in the film, apparently in order to stop them from being sold on the internet. She said in an interview, “It’s all in the closet. One day my daughter can play with it.”
13. Elle has a different hairstyle in almost every scene of the movie.
14. Luke Wilson, who played Emmett, has suggested it wasn't particularly tricky to get into character for the film; "to tell you the truth, I play myself in every movie anyway”.
15. Witherspoon had given birth to her daughter six months prior to making the film and had a lot of sleepless nights during shooting.
16. The actress also said that playing the energetic peppy Elle was “hard work”.
17. Warner’s line “If I want to be a Senator, I need to marry a Jackie, not a Marilyn” is a reference to Jackie Kennedy and Marilyn Monroe.
18. In the original cut, the movie did not end with Elle giving the keynote address at graduation. In that version, Elle passionately kisses Emmett on the stairs of the courthouse and is then shown giving out leaflets for the “Blonde Legal Defense Fund” with a newly blonde Vivian Kensington.
19. This scene was completely rewritten because test audiences disliked the comedy ending.
20. Producer Marc Platt said, "The audience took Elle more seriously than we had anticipated. They wanted to know that she had been very successful." And so the graduation speech and subtitles about Elle’s career success were added.
21. The shoot for the graduation scene took place at Dulwich College, a boys' school in London. Witherspoon was in the country filming The Importance of Being Earnest.
22. MGM filmed a “third” straight-to-DVD sequel called Legally Blondes that didn’t star Witherspoon, although she had a producer credit.
23. In an Instagram Q&A for the 15th anniversary of the film, Reese Witherspoon said, “I have had so many women say to me, ‘I went to law school because of Legally Blonde'.”