Theodore Davis Boal, also known as Terry Boal (June 14, 1867 – August 22, 1938), was an American army officer and architect. He entered into several partnerships over his career, the Boal and Harnois architectural firm in Denver, Colorado and a partnership with Ward Brown in Washington D.C. He designed a number of important mansions that are listed with the National Register of Historic Places. One of his important works, also an NRHP property, is the ancestral family estate, Boal Mansion.
During World War I, Boal and his son volunteered in France before the United States engaged in the war. In 1916, Boal returned to the United States and established the "Boal Troop", a horse-mounted machine gun unit. He was made a Lieutenant Colonel and was awarded the Distinguished Service Cross for valor and the Croix de Guerre in recognition of his service in France.