Lindsay Lohan
Cady Heron

Rachel McAdams
Regina George

Lizzy Caplan
Janis Ian

Lacey Chabert
Gretchen Wieners

Amanda Seyfried
Karen Smith

Daniel Franzese
Damian

Jonathan Bennett
Aaron Samuels

Rajiv Surendra
Kevin Gnapoor

Tina Fey
Ms. Norbury

Tim Meadows
Mr. Duvall

Ana Gasteyer
Cady's Mom

Neil Flynn
Cady's Dad

Amy Poehler
Mrs. George

Dwayne Hill
Coach Carr

Diego Klattenhoff
Shane Oman

Molly Shanahan
Kristen Hadley

Elana Shilling
Spelling Girl

Ely Henry
Homeschooled Boy

Jonathan Malen
Kristen's Boyfriend

Miranda Edwards
Michigan Girl

Les Porter
Chemistry Teacher

Eve Crawford
English Teacher

Jack Newman
History Teacher

Ky Pham
Trang Pak

Daniel DeSanto
Jason

Alisha Morrison
Lea Edwards

Chris Anton
Huge Guy

Jan Caruana
Emma Gerber

Wai Choy
Mathlete Tim Pak

Julia Chantrey
Amber D'Alessio

Olympia Lukis
Jessica Lopez

Stefanie Drummond
Bethany Byrd

Kristen Bone
Short Girl

Andreja Punkris
Animal Dancer

Jordan Dawe
Animal Dancer

Laura de Carteret
Mrs. Wedell

Nicole Crimi
Kylie George

Erin Norah Thompson
Dawn Schweitzer

Dan Willmott
Mr. George

Sharron Matthews
Joan the Secretary

Jill Morrison
Crying Girl

Clare Preuss
Caroline Krafft

Bruce Hunter
Mathlete Moderator

David Reale
Glenn Coco (uncredited)

Krysta Carter
Wannabe (uncredited)