- Billing Displacement: Mekhi Phifer is given less prominence in much of the promotional materials than Josh Hartnett and Julia Stiles; the poster has him tiny at the bottom while Hartnett and Stiles are two floating heads looming above him.
- Enforced Method Acting: The whole cast first performed the play in its original text in rehearsals to get a feel for the drama of the story.
- Dawson Casting: Mekhi Phifer and Josh Hartnett were respectively twenty-four and twenty-one playing high school students. Julia Stiles however was eighteen.
- Distanced from Current Events: The movie was filmed in 1999 but was delayed after the events of Columbine. It was finally released in 2001.
- Dyeing for Your Art: The actors on the basketball team had to go to "basketball camp" for two weeks to learn how to properly play.
- Playing Against Type:
- Josh Hartnett usually found himself playing Lovable Rogue types, and generally good-hearted characters. Iago meanwhile is one of Shakespeare's most sinister villains, and his counterpart Hugo follows suit.
- In the Japanese dub, Hugo is voiced by Hiroaki Hirata, in a role quite unlike those he usually plays.
- The Shelf of Movie Languishment: The official release date was initially set to October 17, 1999, but was not released at that time. One reason, as suggested by its director, was its themes of sex and violence in high school and how that connects to the Columbine High School massacre. Another theory is that it was held back until after the 2000 presidential elections. It was released 31 August 2001.
- The third Setting Update of a Shakespeare play that Julia Stiles played the female lead in, after 10 Things I Hate About You (The Taming of the Shrew) and Hamlet (this was filmed after O but released before it).
- In the Japanese dub, Odin is voiced by Taiten Kusunoki, who is no stranger to Scary Black Man roles.
- What Could Have Been:
- Working Title: Odin, because producers weren't sure about releasing a film with a one letter title. They relented because it was unique, and because 'O' also resembles a basketball hoop.
Trivia / "O"