Freddie Prinze Jr. as Fred

Sarah Michelle Gellar as Daphne

Matthew Lillard as Shaggy

Linda Cardellini as Velma

Neil Fanning as Scooby-Doo Voice / Tasmanian Devil (voice)

Seth Green as Patrick

Peter Boyle as Old Man Wickles

Tim Blake Nelson as Jacobo

Alicia Silverstone as Heather

Pat O'Brien as Pat O'Brien

Bill Meilen as Chauffeur

Zahf Paroo as Ned

Chris Gauthier as Daphne's Tattooed Fan #1

Peter New as Daphne's Tattooed Fan #2

Morgan Brayton as Mullet Nerdette #1

Lisa Ann Beley as Mullet Nerdette #2

Tara Fynn as Mullet Nerdette #3

Brandon Jay McLaren as Skater Dude #2

Aaron Ydenberg as Skater Dude #3

Joe MacLeod as Skater Dude #1

Lou Bollo as Flashback Security Guard #1

John Ulmer as Flashback Security Guard #2

Bradley Gosnell as Kid on Bike #1

Calum Worthy as Kid on Bike #2

Brenna O'Brien as Buttercup Scout

Mark Burgess as Man in Suit

Kwesi Ameyaw as Man in Suit

Ted Kozma as Museum Guard

Darrell Lee-Izeard as Museum Guard

Stephen E. Miller as C.L. Magnus

Karin Konoval as Aggie Wilkins

Paul Jamieson as Scared Man

Andrew McIlroy as Investor

Colin Foo as Investor

Andrew Jackson as Man in Car

Nazanin Afshin-Jam as Shaggy Chick

Cascy Beddow as Young Shaggy

Emily Tennant as Young Daphne

Ryan Vrba as Young Fred

Lauren Kennedy as Young Velma

Jeff Tanner as Harry Lang

A.C. Peterson as Faux Ghost Patron

Dan Joffre as Faux Ghost Patron

Richard Dietl as Pickle Man/Faux Ghost Patron

Bill Mondy as Vomit Reporter

Kimani Ray Smith as Reporter #1

Catherine Lough Haggquist as Reporter #2

Ingrid Torrance as Reporter #3

Tiffani Timms as Reporter #4

Scott McNeil as Evil Masked Figure (voice)

Kevin Durand as Black Knight Ghost

C. Ernst Harth as Miner 49er

Christopher R. Sumpton as Zombie

Ruben Studdard as Ruben Studdard

Dee Bradley Baker as 10,000 Volt Ghost / Zombie / Red Eye Skeleton (voice)

Bob Papenbrook as Black Knight (voice)

Michael Sorich as Tar Monster / Cotton Candy Glob (voice)

Terrence Stone as 10,000 Volt Ghost (voice)

J.P. Manoux as Scooby Brainiac (voice)

Wally Wingert as Green-Eyed Skeleton (voice)