Robin Williams

Professor Philip Brainard

Edie McClurg

Martha George

Clancy Brown

Smith

Christopher McDonald

Wilson Croft

Jodi Benson

Weebo (voice)

David Nicksay

Executive Producer

Scott Michael Campbell

Dale Jepner

Raymond J. Barry

Chester Hoenicker

Ted Levine

Wesson

Leslie Stefanson

Sylvia

Dakin Matthews

Minister

Marcia Gay Harden

Dr. Sara Jean Reynolds

Nancy Olson

Secretary at Ford Motor Company

Wil Wheaton

Bennett Hoenicker

Malcolm Brownson

Father

Benjamin Brock

Window Boy

Zack Zeigler

Teenage Boy

Sam Lloyd

Coach Willy Barker

Scott Martin Gershin

Flubber (voice)

Julie Morrison

Weebette (voice)

Bob Sarlatte

Rutland Coach

Bob Greene

Referee

Tom Barlow

Medfield Basketball Player

Les Mayfield

Director