Martin David Foster (September 3, 1861 – October 20, 1919) was a U.S. Representative from Illinois. Born near West Salem, Illinois, Foster attended the public schools and Eureka College (Illinois). He was graduated from the Eclectic Medical Institute, Cincinnati, Ohio, in 1882 and from the Hahnemann Medical College, Chicago, Illinois, in 1884. He commenced the practice of medicine in Olney, Illinois, in 1884. He served as a member of a board of United States examining surgeons in 1885–1889, and again from 1893 to 1897. He served as mayor of Olney, Illinois, in 1895 and 1902.