- Johan Kaart - Wim Verstappen (voice)
- Cor Witschge - Joris (voice)
- Jenny Arean - Miss Jones' Cat / Kater's Mother (voice)
- Lex Schoorel - Sergeant (voice)
- Rieneke Debree - Kitty (voice)
- Hetty Heyting - Plopje / Miss Jones' Dog (voice)
- Huib Broos - Kater / Professor / Detective / Miss Jones' Horse (voice)
- Trudy Labij - Annabell (voice)
- Willy Brill - Miss Mabel Jones (voice)