Viola Hastings
Viola is the protagonist of the film, an ambitious high school soccer player who takes on her brother's identity in order to play boys' soccer at Illyria High School after the girls' team at her own school gets cut. Viola is an adventurous, energetic young tomboy who does not appreciate any of the expectations of femininity that are placed on her by her more ladylike mother. She just wants to be seen as equal to the boys and respected for who she is.
Sebastian Hastings
Sebastian is Viola's sensitive twin brother who loathes sports and prefers to play in his rock band. He secretly goes to London to play at a festival. Throughout the film, characters comment on the honesty of his lyrics, and his musical talents.
Duke Orsino
Duke is Illyria's soccer captain and Viola's roommate. He is in love with Olivia, but is markedly clumsy and awkward when it comes to women. He does not know what to talk about with girls, and Viola happily coaches him in how to speak to the fairer sex. In the process, and because she is disguised as a guy, Viola comes to see that Duke is actually very sensitive and kind.
Olivia
Olivia is the most popular and beautiful girl at Illyria High. She is shown to be smart, beautiful and sensitive, and is the object of Duke's affection. She does not return Duke's feelings, and is instead taken in by the sensitive understanding of "Sebastian" (who is actually Viola in disguise).
Monique Valentine
Sebastian's ex-girlfriend. She is shown to be very obsessive and controlling.
Justin Drayton
Viola's ex-boyfriend. While he seems like a good guy, he shows his true colors when he fails to stand up for her soccer skills in front of his male teammates.
Malcolm
Malcolm is a nerdy and fussy student who is also in love with Olivia. He suspects that "Sebastian" is hiding something and brings it to the attention of the headmaster. He has a pet tarantula named "Malvolio" (the Shakespeare character on which Malcolm is based).
