Lindsay Lohan
as Cady Heron

Rachel McAdams
as Regina George

Lizzy Caplan
as Janis Ian

Lacey Chabert
as Gretchen Wieners

Amanda Seyfried
as Karen Smith

Daniel Franzese
as Damian

Jonathan Bennett
as Aaron Samuels

Rajiv Surendra
as Kevin Gnapoor

Tina Fey
as Ms. Norbury

Tim Meadows
as Mr. Duvall

Ana Gasteyer
as Cady's Mom

Neil Flynn
as Cady's Dad

Amy Poehler
as Mrs. George

Dwayne Hill
as Coach Carr

Diego Klattenhoff
as Shane Oman

Molly Shanahan
as Kristen Hadley

Elana Shilling
as Spelling Girl

Graham Kartna
as Homeschooled Boy

Ely Henry
as Homeschooled Boy

David Aherne
as Homeschooled Boy

Ayo Agbonkpolo
as African Warrior

Jonathan Malen
as Kristen's Boyfriend

Jeff Moser
as "Farting" Guy

Miranda Edwards
as Michigan Girl

Les Porter
as Chemistry Teacher

Eve Crawford
as English Teacher

Jack Newman
as History Teacher

Michelyn Emelle
as Music Teacher

Bathsheba Garnett
as German Teacher

Ky Pham
as Trang Pak

Danielle Nguyen
as Sun Jin Dinh

Daniel DeSanto
as Jason

Alisha Morrison
as Lea Edwards

Chris Anton
as Huge Guy

Jan Caruana
as Emma Gerber

Wai Choy
as Mathlete Tim Pak

Julia Chantrey
as Amber D'Alessio

Jacky Chamberlain
as Giselle Sgro

Olympia Lukis
as Jessica Lopez

Stefanie Drummond
as Bethany Byrd

Kristen Bone
as Short Girl

Jessie Wright
as Cady 5 Years Old

Tyson Fennell
as Nfume

Stephan Dickson
as Animal Dancer

Andreja Punkris
as Animal Dancer

Noelle Boggio
as Animal Dancer

Jordan Dawe
as Animal Dancer

Alexandra Stapley
as Taylor Wedell

Laura de Carteret
as Mrs. Wedell

Nicole Crimi
as Kylie George

Erin Norah Thompson
as Dawn Schweitzer

Dan Willmott
as Mr. George

Michelle Hoffman
as Kissing Girl

Valerie Casault
as Kissing Girl

Sharron Matthews
as Joan the Secretary

Jo Chim
as Salesperson

Randi Lee Butcher
as Skater Girl

Erin Jarvis
as Skater Girl

Kaylen Christensen
as Jock Girl

Jill Morrison
as Crying Girl

David Sazant
as Marymount Captain

Clare Preuss
as Caroline Krafft

Bruce Hunter
as Mathlete Moderator

Megan Millington
as Junior Plastic

Tara Shelley
as Junior Plastic

Shannon Todd
as Junior Plastic

David Reale
as Glenn Coco (uncredited)

Krysta Carter
as Wannabe (uncredited)