"In 1965, Rees was awarded the Achievement Award by the American Association of University Women, an award given annually in honor of women who have made outstanding contributions in their fields.The Public Welfare Medal, the highest honor of the National Academy of Sciences, 1983, "in recognition of distinguished contributions in the application of science to the public welfare...for her contributions to the scientific enterprise, especially in mathematics, astronomy, and computer sciences, from wartime, through the transition from war to peace, and continuing today."