William Thomas Councilman (1854-1933) was an American pathologist. He was the son of Dr. John T. Councilman (1815-1890), a rural physician. He studied medicine for two years in the medical school at the University of Maryland, then at the Johns Hopkins University. He was interested in histological pathology, so he travelled to Europe for intensive training. He helped John Shaw Billings (1838-1913) prepare his National Medical Dictionary and performed autopsies at Bayview where for one year he served as the coroner's physician to the city. In 1892 he was appointed Shattuck professor of pathological anatomy at Harvard. He is remembered for his contribution in a monograph on amoebic dysentery (1891) which described detailed observations of it and its parasite.