Daniel Willett Foster (March 4, 1930 – January 25, 2018) was the John Denis McGarry, Ph.D. Distinguished Chair in Diabetes and Metabolic Research and Professor of Internal Medicine at the University of Texas Southwestern Medical School at Dallas. He was Chairman of the Department of Internal Medicine for 16 years. He was a Fellow of the American Academy of Arts and Sciences, a Fellow of the American Association for the Advancement of Science and a member of the Institute of Medicine of the National Academies. He was a Master of the American College of Physicians. He was also a former member of the President's Council on Bioethics.