- Thomas as Lewis
- Duck as Willbur
- Percy as Goob
- Smudger as Michael Yoobain
- James as Mr. Willinsten
- Duncan as Mr. Harrington
- Diesel 10 as Tiny
- Gordon as Gym Coach
- Henry as Lazlo
- Edward as Stanley
- Rosie as Dr. Crucklehorn
- Oliver as Carl
- Daisy as Doris
- Donald/Douglas as Bud
see also