Cady Heron
Cady is the film's protagonist, a naive teen girl who has been homeschooled for 12 years while living in Africa with her research zoologist parents. Her first day in an American public high school is a "trial by fire" introduction to the treacherous world of cliques and hierarchies that have already been formed before her arrival. Cady is intelligent, especially in math, and eager to be liked. At the beginning of the film, she accepts the friendly overtures of Janis and Damian as well as their rivals The Plastics, trying to remain non-judgmental. Cady eventually succumbs to the seductive but cruel lure of the popular crowd, before redeeming herself in the end.
Regina George
Cady describes Regina George as a living Barbie doll: blonde, beautiful, glamorous, wealthy, capable, and seemingly carefree. She is the leader of "The Plastics"—an exclusive clique consisting of only her, Gretchen Wieners, and Karen Smith. We see Regina's impressive savagery early on in the film, like when she dispatches Jason for Cady in the cafeteria, or prank-calls his girlfriend's mom in the mall. Even as Cady realizes that Regina's cruelty knows no bounds, she aspires to take Regina's place. Regina is hit by a bus toward the end of the film, and in the epilogue has joined the lacrosse team to channel her anger.
Gretchen Wieners
Gretchen Wieners has two defining qualities: being the heiress to a dubious "Toaster Strudel" fortune, and having many "secrets." She often seems like Regina's second-in-command, occasionally acting as Regina's representative, and stringently enforcing the bylaws of The Plastics. Early on, she seems delighted and empowered knowing Cady's "secret" (liking Aaron Samuels), and later divulges all of Regina's secrets when feeling panicked and insecure. At the end of the film she has begun hanging out with the "cool Asians" clique.
Karen Smith
Karen is the third member of The Plastics, notable mainly for her sheer stupidity. Karen's dim wit makes her an easy member of the group to target and manipulate, like Cady does toward the end of the film with a "three-way calling attack." Karen fails to understand basic matters in the film, like why Cady is white, or what "first cousin" means. She often uses malapropisms, like referring to ESP as "ESPN." At the end of the film, Karen fulfills her dream of being a weather girl.
Janis Ian
Janis is the first person Cady meets at school, along with Damian. In addition to providing Cady with background information on the school's notable personalities, along with Damian, Janis gives Cady a literal map of the school cafeteria and its various territorial boundaries. Janis hates Regina because they used to be friends until Regina began spreading rumors about Janis being a lesbian, leading her to drop out of school and become a Goth. Janis's crude wisdom in fact provides the moral center of the film, veering Cady away from the influence of The Plastics.
Aaron Samuels
Aaron Samuels is a high school senior and Cady's classmate in calculus class. Aaron's "boy-next-door" good looks cause Cady to like him, although Gretchen forbids her from acting on the crush because Aaron is Regina's ex. After a jealous Regina seduces Aaron in front of Cady, Cady successfully schemes to break up their relationship. Aaron hesitates to date Cady after she starts styling herself after Regina, and only reunites with her at the film's end during the Spring Fling concert.
Ms. Norbury
Ms. Norbury is a divorced math teacher who encourages Cady to join the Mathletes. Ms. Norbury on occasion acts as Cady's conscience, not only encouraging her to pursue math, something Cady resists so she can endear herself to Aaron, but encouraging her to come clean and accept blame for her involvement in the Burn Book. Cady's most hurtful comments in the Burn Book are directed toward Ms. Norbury, and lead to her office being searched by police. Ms. Norbury lectures the assembly of junior girls about the ramifications of their behavior, and is last seen dancing at the Spring Fling with Mr. Duvall.
Damian
Damian is best friends with Janis, and the first classmate at school to talk to Cady. Janis describes him early on as being almost "too gay to function," and Damian certainly has an eye for glitz and glamour, as evidenced by the Mariah Carey posters on his bedroom wall, and his performance of "Beautiful" by Christina Aguilera at the Winter Talent Show. Like Janis, Damian hates Regina, but on a certain level still admires the "fabulous" aura she is able to project.
