Marie Warder (born Marie van Zyl, 30 April 1927 – 20 October 2014) was a South African-born Canadian journalist, novelist and activist best known for her activities raising awareness about hemochromatosis. Warder founded the Hemochromatosis Society of South Africa, and the Canadian Hemochromatosis Society (CHS), and was founder and long-time president of the International Association of Hemochromatosis Societies (IAHS), writing the detailing leaflets for them all, which meant that, at that stage, every publication of the Canadian Hemochromatosis Society carried the footnote: "Produced for the International Association of Haemochromatosis Societies."