Katherine Stewart MacPhail OBE (30 October 1887 - 11 September 1974) was a Scottish surgeon. During World War I, she served as Chief Medical Officer of two units of the Scottish Women's Hospitals for Foreign Service. She cared for the wounded in Serbia, France, and the Thessaloniki Front. In 1921, during her stay in Serbia, she founded the country's first children's hospital. While she is remembered as a national hero in Serbia, she was criticized by some for providing her expertise in Serbia rather than in her own country. Her honors include several medals, plaques, and a postage stamp.