Lisa Kudrow received a degree in Biology from Vassar College, and Mira Sorvino a degree in Asian Studies from Harvard University, so during production of Romy and Michele, they nicknamed each other "Smart" and "Smarter."
In the dream reunion scene, when Romy and Michelle are on stage to receive their award, you can see just above the stage in the lights that are strung what looks like a banana on one side, and a carrot on the other just like the magnets that Christie put on Michelle's back brace in high school.
In one scene, Christy played a trick on Michelle by putting magnets on her back brace. The actress who played Christy, Julia Campbell, wore a back brace in real life when she developed scoliosis at age 11. At 15, she had to have corrective surgery when her spine started cutting into her right lung. She has since recovered but cannot partake in any physical activities that puts pressure on her spine.
The trailer has a small bit of dialog edited out of the movie: In a scene from the film used in the trailer, Michele tells the A-list girls "We're not the ones who got fat," to which Christine replies "We're pregnant." In the trailer Michele then retorts "Okay, we're not the ones who got pregnant," but this line does not appear in the movie.
Sandy's arrival and exit at the reunion in a helicopter is a reference to Don Simpson's. Simpson once felt compelled to arrive to his twentieth reunion in his helicopter with two Playboy Playmates (or Penthouse Pets depending on source), showed his face there for 30 minutes and left with them.
Many actors in this movie played small roles in "Friends", Lisa Kudrow's most famous work. Julia Campbell and Elaine Hendrix were Ross's love interests. Vincent Ventresca played Monica's on and off boyfriend "Fun Bobby". Plus, it's common knowledge that Janeane Garofalo turned down the role of Monica. And Jennifer Aniston married Justin Theroux, who plays the cowboy in R&M.
In an episode of HBO's "The Comeback," Lisa Kudrow's "Valerie Cherish" walks through a metal detector only to reveal she has a rod down her back due to her having scoliosis as a teen, much like Michele having scoliosis in the film.
During the Senior Prom flashback, Romy & Michelle are dressed in the style of Madonna. However Romy's costume is meant to reflect Madonna's Vogue-era style, which didn't come out until 1990. Which is 3 years later than they would have graduated, considering their 10-year reunion takes place in 1997, meaning they graduated in 1987.