 | Robin Williams als Professor Philip Brainard |
 | Marcia Gay Harden als Dr. Sara Jean Reynolds |
 | Christopher McDonald als Wilson Croft |
 | Raymond J. Barry als Chester Hoenicker |
 | Clancy Brown als Smith |
 | Nancy Olson als Secretary at Ford Motor Company |
 | Ted Levine als Wesson |
 | Wil Wheaton als Bennett Hoenicker |
 | Edie McClurg als Martha George |
 | Jodi Benson als Weebo (voice) |
 | Leslie Stefanson als Sylvia |
 | Malcolm Brownson als Father |
| Benjamin Brock als Window Boy |
 | Dakin Matthews als Minister |
| Zack Zeigler als Teenage Boy |
 | Sam Lloyd als Coach Willy Barker |
 | Scott Martin Gershin als Flubber (voice) |
 | Julie Morrison als Weebette (voice) |
| Bob Sarlatte als Rutland Coach |
 | Scott Michael Campbell als Dale Jepner |
| Bob Greene als Referee |
| Tom Barlow als Medfield Basketball Player |
| Les Mayfield | Director |
| John Hughes | Screenplay |
| Bill Walsh | Screenplay |
| John Hughes | Producer |
| Ricardo Mestres | Producer |
| David Nicksay | Executive Producer |
| Dean Cundey | Director of Photography |
| Harvey Rosenstock | Editor |
| Michael A. Stevenson | Editor |
| Matsune Suzuki | Modeling |
| Nancy Foy | Casting |
| Danny Elfman | Original Music Composer |
| Michael Polaire | Co-Producer |
| April Ferry | Costume Design |
| Peter Crosman | Visual Effects Supervisor |
| Tom Bertino | Visual Effects Supervisor |
| Douglas Smith | Visual Effects Supervisor |
| Andrew McAlpine | Production Design |
| Wylie Stateman | Supervising Sound Editor |
| Scott Martin Gershin | Supervising Sound Editor |
| James E. Tocci | Art Direction |
| Keith Neely | Assistant Art Director |
| Erin Kemp | Set Designer |
| Daniel Loren May | Set Decoration |
| Cheri Minns | Makeup Supervisor |
| Marianna Åström-De Fina | Makeup Artist |
| Kris Ravetto | Makeup Artist |
| Carol A. O'Connell | Key Hair Stylist |
| Mariann Ybarra | Hairstylist |
| Stan Parks | Special Effects Coordinator |
| Daniel Sudick | Special Effects Supervisor |
| Rochelle Gross | Visual Effects Coordinator |
| Tom Bertino | Animation Supervisor |
| Roni McKinley | Visual Effects Producer |
| Sandra Ford Karpman | Visual Effects Supervisor |
| Lynda Thompson | Visual Effects Producer |
| Michael Polaire | Unit Production Manager |
| Matthew H. Rowland | First Assistant Director |
| Angela C. Tortu | Second Assistant Director |
| Freddie Hice | Stunt Coordinator |
| Daniel B. Clancy | Leadman |
| Joseph Markham | Costume Supervisor |
| Amy J. Smith | Costumer |
| Casey Hotchkiss | Camera Operator |
| William Coss | First Assistant Camera |
| Lynetta Freeman | Second Assistant Camera |
| Carol DePasquale | Script Supervisor |
| Michael Orefice | Chief Lighting Technician |
| Terry Sullivan | Best Boy Electric |
| Jason Boccaleoni | Electrician |
| Tom Cloutier | Electrician |
| Stephen J. Gardner | Assistant Property Master |
| Roy Augenstein | Special Effects Technician |
| Jessica Gallavan | ADR Supervisor |
| Ellen Segal | Music Editor |
| Andrew Somers | Sound Effects Editor |
| Bryan Bowen | Sound Effects Editor |
| Chris Hogan | Sound Effects Editor |
| Michael A. Reagan | Sound Effects Editor |
| Dino DiMuro | Sound Effects Editor |
| Richard Dwan Jr. | Sound Effects Editor |
| Dan Hegeman | Sound Effects Editor |
| Peter Zinda | Sound Effects Editor |
| Constance A. Kazmer | Dialogue Editor |
| Lauren Stephens | Dialogue Editor |
| Mark Gordon | Dialogue Editor |
| Dan M. Rich | Dialogue Editor |
| Kimberly Lowe Voigt | ADR Editor |
| Larry Kemp | ADR Editor |
| John K. Adams | ADR Editor |
| Arthur Farkas | Foley Editor |
| Michelle Pazer | Sound Assistant |
| David Stanke | Sound Assistant |
| Lee W. Lebaigue | Sound Assistant |
| David W. Alstadter | Foley Mixer |
| Doc Kane | ADR Mixer |
| Mike Boudry | ADR Recordist |
| James Moriana | Foley Artist |
| Catherine Harper | Foley Artist |
| Terry Porter | Sound Re-Recording Mixer |
| Mel Metcalfe | Sound Re-Recording Mixer |
| Dean A. Zupancic | Sound Re-Recording Mixer |
| Rory Enke | Location Manager |
| Phil Bray | Still Photographer |
| Michael Umble | Unit Publicist |
| Kenny Searle | Transportation Coordinator |
| Robert K. Johnson | Transportation Captain |
| Suzy Sharp-Kane | Casting Associate |
| Beau Bonneau | Extras Casting |
| Barbara Harris | ADR Voice Casting |
| Bob Putynkowski | Color Timer |
| Peter Crosman | Second Unit Director |
| Raymond Stella | Second Unit Director of Photography |
| Howard E. Baker | Animation Supervisor |
| Steve Bartek | Orchestrator |
| Troy Gilbert | Stunts |
| Heather Burton | Stunts |
| Troy Robinson | Stunt Double |
| Troy Brown | Stunt Double |
| Samuel W. Taylor | Short Story |
| Steve Kelso | Stunts |
