William Sprague, also known as William III or William Sprague III, was a politician and industrialist from the U.S. state of Rhode Island, serving as the 14th Governor, a U.S. Representative and a U.S. Senator. He was the uncle of William Sprague IV, also a Governor and Senator from Rhode Island.

William Sprague IV was the 27th Governor of Rhode Island from 1860 to 1863, and U.S. Senator from 1863 to 1875. He participated in the First Battle of Bull Run during the American Civil War while he was a sitting Governor.