The boys will get a new class teacher who has discipline, they get in a lot of mischief, so much complaints that they have to read extra during the summer holidays to get started in class 4.
| Actor | Role |
|---|---|
 Sigurd WallénDr. Wahlberg | Dr. Wahlberg |
 Björn BerglundDr. Sune Gans | Dr. Sune Gans |
 Frithiof HedvallPrincipal | Principal |
 Carl-Gunnar WingårdEmil Nilsson | Emil Nilsson |
 Millan BolanderMrs. Nilsson | Mrs. Nilsson |
 Ann Mari UddenbergLaura | Laura |
 Sven-Eric GambleSigge | Sigge |
 Åke JohanssonPutte | Putte |
 Nils HallbergFredrik 'Dudde' Vedlund | Fredrik 'Dudde' Vedlund |
 Erik A. PetschlerSong teacher | Song teacher |
 Ludde JubergTeacher | Teacher |
 Märtha LindlöfMiss Boronius | Miss Boronius |
| GGerda BomanMrs. Björklund | Mrs. Björklund |
| SSigne Lundberg-SettergrenMina (Nilsson's housemaid) | Mina (Nilsson's housemaid) |
 Yngve NyqvistSchoolteacher | Schoolteacher |
 Anders FrithiofSchool janitor | School janitor |
| BBertil HellqvistNils-Georg Björklund | Nils-Georg Björklund |