 Rex HarrisonDr. John Dolittle | Dr. John Dolittle |
 Samantha EggarEmma Fairfax | Emma Fairfax |
 Anthony NewleyMatthew Mugg | Matthew Mugg |
 Richard AttenboroughAlbert Blossom | Albert Blossom |
 Peter BullGeneral Bellowes | General Bellowes |
 Muriel LandersMrs. Blossom | Mrs. Blossom |
 William DixTommy Stubbins | Tommy Stubbins |
 Geoffrey HolderWilliam Shakespeare X | William Shakespeare X |
 Portia NelsonSarah Dolittle | Sarah Dolittle |
 Norma VardenLady Fetherington | Lady Fetherington |
 Frank BakerTrial Spectator (uncredited) | Trial Spectator (uncredited) |
| EEdward CastPrison Guard (uncredited) | Prison Guard (uncredited) |
| PPhyllis CoghlanCourtroom Spectator (uncredited) | Courtroom Spectator (uncredited) |
| RRobert ColeRoustabout (uncredited) | Roustabout (uncredited) |
| CCyril CrossCharlie (uncredited) | Charlie (uncredited) |
| PPeter CrowcroftAssistant Judge (uncredited) | Assistant Judge (uncredited) |
| JJohn DolanFisherman (uncredited) | Fisherman (uncredited) |
 Jesslyn FaxOld Woman (uncredited) | Old Woman (uncredited) |
 Arthur Gould-PorterSir Rupert (uncredited) | Sir Rupert (uncredited) |
| EEric HeathCourtroom Spectator (uncredited) | Courtroom Spectator (uncredited) |
| LLars HensenMinor Role (uncredited) | Minor Role (uncredited) |
 Kendrick HuxhamElderly Man (uncredited) | Elderly Man (uncredited) |
| TTheron JacksonBoy (uncredited) | Boy (uncredited) |
 Queenie LeonardCourtroom Spectator (uncredited) | Courtroom Spectator (uncredited) |
| FFrank RadcliffeStrong Man (uncredited) | Strong Man (uncredited) |
 Jack RaineVicar (uncredited) | Vicar (uncredited) |
| DDanny ReesJuggler (uncredited) | Juggler (uncredited) |
 Angelo RossittoDwarf (uncredited) | Dwarf (uncredited) |
 RufusDog (uncredited) | Dog (uncredited) |
 Ted StanhopeAssistant Judge (uncredited) | Assistant Judge (uncredited) |
