Marianne Muis is a swimmer who has competed for the Netherlands. She competed at the 1988, 1992, and 1996 Summer Olympic Games.
Muis arrived at her first Olympics in 1988 with her twin sister Mildred as members of the Dutch swimming team. In the 4x100 metres freestyle relay, she trailed the initial leg with a marginal lead before she handed Mildred and three-time Olympian Conny van Bentum their relay duties at the next exchange to boot the Dutch women toward the front. With Van Bentum passing the Americans by 0.08 of a second near the final exchange, she witnessed her other teammate Karin Brienesse record the eighth fastest split of all time on the last leg to secure a runner-up spot for the Dutch women.
Muis has continued to be a member of the Dutch swimming team at Barcelona 1992 and Atlanta 1996, but she and her teammates failed to reproduce a similar outcome in all of their relay races from Seoul. She barely missed the podium twice by a full second or more behind the Germans in 4x100 metres freestyle.
On the individual side, Muis' foremost result transpired in the 200 metres individual medley at her Olympic debut in Seoul where she placed fifth in the final.
Olympic Results[]
| Year | Event | Rank |
|---|---|---|
| 1988 | Women's 200m individual medley | 5th |
| Women's 400m individual medley | 20th | |
| Women's 4x100m freestyle relay | 
| |
| 1992 | Women's 50m freestyle | 11th |
| Women's 4x100m freestyle relay | 5th | |
| Women's 4x100m medley relay | 8th | |
| 1996 | Women's 50m freestyle | 9th |
| Women's 4x100m freestyle relay | 4th |
1988[]
| Discipline | Round | Time | |
|---|---|---|---|
| 200 metres individual medley | Heats | 2:16.60 | |
| A Final | 2:16.40 | ||
| 400 metres individual medley | Heats | 4:56.31 | |
| Final | Did not advance | ||
| 4x100 metres freestyle relay | Heats | 3:44.12 (55.96 split) |
|
| Final | 3:43.39 (56.26 split) |
NR | |
1992[]
| Discipline | Round | Time |
|---|---|---|
| 50 metres freestyle | Heats | 26.43 |
| B Final | 26.24 | |
| 4x100 metres freestyle relay | Heats | 3:44.00 (55.51 split) |
| Final | 3:43.74 (55.53 split) | |
| 4x100 metres medley relay | Heats | 4:11.25 (55.58 split) |
| Final | 4:10.87 (55.37 split) |
1996[]
| Discipline | Round | Time | |
|---|---|---|---|
| 50 metres freestyle | Heats | 25.93 | |
| B Final | 25.74 | ||
| 4x100 metres freestyle relay | Heats | 3:43.63 (55.60 split) |
|
| Final | 3:42.40 (55.73 split) |
NR |