Robin Williams

Professor Philip Brainard

Marcia Gay Harden

Dr. Sara Jean Reynolds

Christopher McDonald

Wilson Croft

Raymond J. Barry

Chester Hoenicker

Clancy Brown

Smith

Nancy Olson

Secretary at Ford Motor Company

Ted Levine

Wesson

Wil Wheaton

Bennett Hoenicker

Edie McClurg

Martha George

Jodi Benson

Weebo (voice)

Leslie Stefanson

Sylvia

Dakin Matthews

Minister

Sam Lloyd

Coach Willy Barker

Scott Martin Gershin

Flubber (voice)

Julie Morrison

Weebette (voice)

Scott Michael Campbell

Dale Jepner