| Birth Date: | 28 April 1928 |
| Birth Place: | Stockholm, Sweden |
| Sport: | Swimming |
| Club: | Stockholms KK |
Karl Bengt Rask (born 28 April 1928) is a retired Swedish swimmer who won a bronze medal relay medals in the 200 m breaststroke at the 1950 European Aquatics Championships. Two years later he competed in the same event at the 1952 Summer Olympics but was eliminated in the preliminaries.