| Birth Name: | Marcelien de Koning |
| Full Name: | Marcelien Bos-de Koning |
| Nationality: | Dutch |
| Birth Date: | 10 May 1978 |
| Birth Place: | Hoorn, Netherlands |
| Height: | 1.75m (05.74feet) |
| Classes: | Europe 470 Elliott 6m |
| Club: | Watersportvereniging Hoorn |
| Show-Medals: | yes |
| Updated: | 13 February 2014 |
Marcelien Bos-de Koning (born 10 May 1978) is a Dutch three-time world champion and Olympic silver medalist sports sailor. She represented her country at the 2008 Summer Olympics in Qingdao. With crew member Lobke Berkhout Bos-de Koning took the silver medal as helmsman in the Women's 470. Bos-de Koning returned as crew member to the 2012 Olympic match regatta's in Weymouth in the Elliott 6m. With helmsman Renee Groeneveld and fellow crew member Annemieke Bes Bos-de Koning took 8th place.
Bos-de Koning held the following positions within the International Sailing Federation: