Malachi Pearson as Casper (voice)

Christina Ricci as Kathleen 'Kat' Harvey

Bill Pullman as Dr. James Harvey

Cathy Moriarty as Carrigan Crittenden

Eric Idle as Paul 'Dibbs' Plutzker

Joe Alaskey as Stinkie (voice)

Joe Nipote as Stretch (voice)

Brad Garrett as Fatso (voice)

Devon Sawa as Casper on Screen

Dan Aykroyd as Dr. Raymond Stantz (uncredited)

Chauncey Leopardi as Nicky

Spencer Vrooman as Andreas

Garette Ratliff Henson as Vic DePhillippi

Jessica Wesson as Amber Whitmire

Amy Brenneman as Amelia Harvey

Ben Stein as Mr. Rugg

Don Novello as Father Guido Sarducci

Terry Murphy as Terry Murphy ('Hard Copy')

Ernestine Mercer as Woman Being Interviewed

Doug Bruckner as Reporter (voice)

John Kassir as The Crypt Keeper (voice)

Wesley Thompson as Mr. Curtis

Michael Dubrow as Student #1

J.J. Anderson as Student #2

Jess Harnell as Arnold (voice)

Michael McCarty as Drunk in Bar

Micah Winkelspecht as Student

Mike Simmrin as Phantom

Rodney Dangerfield as Rodney Dangerfield (uncredited)

Clint Eastwood as Clint Eastwood (uncredited)

Mel Gibson as Mel Gibson (uncredited)

Elise Main as Little Red Riding Hood (uncredited)

Tony Stef'Ano as Kid at Party (uncredited)

Bill Farmer as Fatso's Burping (uncredited)

Harry Shearer as Radio announcer (uncredited)