| Birth Place: | Vlaardingen, the Netherlands |
| Height: | 1.67m (05.48feet) |
| Weight: | 63kg (139lb) |
| Sport: | Swimming |
| Club: | VZC, Vlaardingen |
| Show-Medals: | yes |
Marianne Vermaat (born 2 May 1955) is a former backstroke swimmer from the Netherlands, who competed for her native country at the 1972 Summer Olympics in Munich, West Germany. There she was eliminated in the semi-finals of the 100 m backstroke, clocking 1:09.11 (16th place).