The Karlsson Brothers is a "confusion" comedy about two identical-twin brothers, each initially unaware of the other's existence. One brother is a successful, perfectionist lawyer living in Stockholm. The other brother lives in the North of Sweden with a wife and children, and is a notoriously unfaithful ne'er-do-well. The brothers meet for the first time as they go through their deceased mother's estate. Their meeting leads to a series of challenging mix-ups, turning both their lives on end. The brothers' differences prove gradually to be a source of strength, and their newfound friendship will change their lives forever.
| Actor | Role |
|---|---|
 Björn BengtssonNicklas & Hasse | Nicklas & Hasse |
 Tuva NovotnyClara | Clara |
 Jessica ZandénLisbeth | Lisbeth |
 Vanna RosenbergMona | Mona |
 Johan RabaeusBo | Bo |
 Per AnderssonJesper | Jesper |
 Fredrik HillerPeter - Security Guard | Peter - Security Guard |
| JJens NilssonHenrik - Security Guard | Henrik - Security Guard |
| KKerstin SteinbachMonika | Monika |
 Rolf DegerlundBergmark | Bergmark |
| MMargareta GudmundsonBirgitta - Receptionist | Birgitta - Receptionist |
| CCarl-Philip AnderssonMelvin | Melvin |
 Jonathan AnderssonÅke | Åke |
| TTherese LindbergDate | Date |
 Björn ElgerdFilip | Filip |
| JJohanna GranströmMia - Date 2 | Mia - Date 2 |
| ÅÅsa PerssonPolice officer | Police officer |
| LLinn Bjørnvik GrøderMadeleine | Madeleine |
| LLinda WincentProsecutor | Prosecutor |
| AAnna-Yrsa FaleniusMidwife | Midwife |
| AAlexander KarlssonGäst | Gäst |
 Henrik KvarnlötPolice Officer | Police Officer |