Dr. Donald Warren Leonard (April 7, 1903 - February 21, 1950) was an American medical doctor. Born in Newtonville, Massachusetts, Leonard attended medical school at Harvard and graduated in 1929. He moved to Exeter, New Hampshire in 1931, where he established himself as a general practitioner and as a member of the staff of the Exeter hospital. He served as a member of the Exeter Hospital corporation and was a member of the American Medical Association, the New Hampshire Medical Association and the Rockingham County Medical Society. He was also a Fellow of the American College of Surgeons. He also served as secretary-treasurer of the Rockingham County Medical Society and was the editor of the Rockingham County Medical Society News, the group's monthly newsletter. Leonard married Mary Heilig, with whom he had one daughter.