Frank Welker

Character: Scooby-Doo / Fred Jones / Self

Matthew Lillard

Character: Norville 'Shaggy' Rogers / Self - Voice of "Shaggy"

Grey DeLisle

Character: Daphne Blake / Self - Voice of "Daphne"

Kate Micucci

Character: Velma Dinkley / Self - Voice of "Velma"

Janel Parrish

Character: Janel Parrish - Host

Jerry Beck

Character: Self - Animation Historian and Author

David Silverman

Character: Self - Director and Producer, "The Simpsons"

Seth Green

Character: Self - Actor, "Scooby-Doo 2: Monsters Unleashed"

Tony Cervone

Character: Self - Director, "Scoob!" / Showrunner, "Mystery Incorporated"

Tom Sito

Character: Self - Animator, Historian

Joseph Barbera

Character: Self - Hanna-Barbera Co-Founder (archive footage)

Mary Lynn Rajskub

Character: Producer Bryn

Baron Vaughn

Character: Bram Penobscot - Scooby's Vocal Coach

Casey Kasem

Character: Shaggy Rogers (voice) (archive footage)

Diedrich Bader

Character: Batman - Concerned Citizen (voice)

'Weird Al' Yankovic

Character: Self - Singer, Songwriter, Accordionist

Olivia Liang

Character: Olivia Liang - Shaggy's Martial Arts Trainer

Karamo Brown

Character: Costume Designer Carter

Mitch Watson

Character: Self - Showrunner, "Mystery Incorporated"

Cheri Oteri

Character: Lazlo the Mechanic

Brendan Jennings

Character: Arlo Davidsonman - Team Scooby

Vadym Krasnenko

Character: Snow Ghost

Lindsey Alena

Character: Additional Voices (voice)

Dominic Catrambone

Character: Additional Voices (voice)

Fred Tatasciore

Character: Additional Voices (voice)