Matthew Broderick

John Brown / Inspector Gadget / Robo Gadget

Rupert Everett

Sanford Scolex / Dr. Claw

Joely Fisher

Brenda / Robobrenda

Michelle Trachtenberg

Penny

Andy Dick

Kramer

Cheri Oteri

Mayor Wilson

Mike Hagerty

Sikes

Dabney Coleman

Chief Quimby

D.L. Hughley

Gadgetmobile (voice)

René Auberjonois

Artemus Bradford

Frances Bay

Thelma

Laurence Tureaud

Himself

Richard Kiel

Famous Big Guy with Silver Teeth

Richard Lee-Sung

Famous Villain with Deadly Hat

Bobby Bell

Famous Identifier of Sea Planes

Hank Barrera

Famous Native American Sidekick

Keith Morrison

Famous Assistant to Dr. Frankensomething

John Kim

Son Before Second Son

Jesse Yoshimura

Bane of the Bumbling / Robobrendaerobics Group Member

Aaron Meyerson

Aaron Meyerson

Cliff Emmich

Out of Control Bus Driver

Richard Penn

Fantastic Doctor

J.P. Manoux

Mayor's Sychophantic Assistant

Brian George

Sore Guru

Alexander Witt

Wet, Green Businessman

E.J. Callahan

Hot Dog Vendor

Chad Parker

Assistant Car Thief

Frank Masi

Period Photographer

Mary Chris Wall

Snoopy News Anchor

Linda Cevallos

Showgirl

Loralyn Peterson

Showgirl

Andy Heyward

Mr. D.I.C. - Party Guest

Don Adams

Brain (voice)

Danny Nero

Police Officer (uncredited)