Megan Fox as Jennifer

Amanda Seyfried as Needy

Johnny Simmons as Chip

Adam Brody as Nikolai

Sal Cortez as Chas

Ryan Levine as Mick

Juan Riedinger as Dirk

Colin Askey as Keyboardist

Chris Pratt as Roman Duda

Juno Rinaldi as Officer Warzak

Kyle Gallner as Colin Gray

Josh Emerson as Jonas Kozelle

J.K. Simmons as Mr. Wroblewski

Amy Sedaris as Needy's Mom

Cynthia Stevenson as Chip's Mom

Nicole Leduc as Camille

Aman Johal as Ahmet from India

Dan Joffre as Raymundo

Candus Churchill as Nutritionist

Carrie Genzel as Jennifer's Mom

Emma Gallello as Little Jennifer

Megan Charpentier as Little Needy

Jeremy Schuetze as Craig

Valerie Tian as Chastity

Emily Tennant as Gossiping Girl

Karissa Tynes as Other Girl

Eve Harlow as Goth Girl

Michael Brock as Goth Boy

Genevieve Buechner as Goth Girl #2

Adrian Hough as Colin's Dad

Gabrielle Rose as Colin's Mom

Michael Bean as Priest

Bill Fagerbakke as Jonas' Dad

Marilyn Norry as Jonas' Mom

Cut Chemist as DJ at Dance

Zoe LaLiberté as Candlelight Vigil Singer

Chelsey Smith as Candlelight Vigil Singer

Whitney Chow as Candlelight Vigil Singer

Michael Orstad as Candlelight Vigil Singer

Ronnie Robinson as Orderly

Ed Anders as Orderly

Roxanne Wong as Patient #1

Diane Dutra as Patient #2

Maya Toews as The Creepy Hand

Diablo Cody as Melody Lane Drinking Woman (uncredited)

Lance Henriksen as Passing Motorist (uncredited)