William Gaston was a lawyer and politician from Massachusetts. A Democrat, he was the first member of that party to serve as Governor of Massachusetts (1875–1876) after the American Civil War. He was a successful trial lawyer and politically conservative Democrat, who won election as governor after his opponent, Thomas Talbot, vetoed legislation to relax alcohol controls.

The governor of the Commonwealth of Massachusetts is the chief executive officer of the government of Massachusetts. The governor is the head of the state cabinet and the commander-in-chief of the commonwealth's military forces.