Marlies Oostdam (born 29 July 1977 in Haarlem, Netherlands) is a football (soccer) player who represented New Zealand at international level. She emigrated from the Netherlands to New Zealand in 1985. 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, 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).