Mirjam van Hemert (born 30 September 1950) is a retired Dutch swimmer who won a bronze medal in the 4×100 m freestyle relay at the 1966 European Aquatics Championships. She also competed at the 1968 Summer Olympics in the 100 m freestyle and 4×100 m freestyle relay, but failed to reach the finals. She won a national title in the 100 m freestyle in 1968.