Marlies Oostdam (born 29 July 1977 in Haarlem, Netherlands) is a football (soccer) player who represented New Zealand at international level.

Oostdam made her full Football Ferns debut in a 0–3 loss to Australia on 24 March 1996, and represented New Zealand at the 2007 FIFA Women's World Cup finals in China,[2] where they lost to Brazil (0–5), Denmark (0–2) and China (0–2).

Oostdam was also included in the New Zealand squad for the 2008 Summer Olympics where they drew with Japan (2–2) before losing to Norway (0–1) and Brazil (0–4).

[3] Oostdam formally played for Melbourne Victory in the Australian W-League.

This biographical article related to women's association football in New Zealand is a stub.