Quintus et Ultimus Watson, also known as Q. U. Watson, was an American politician from Texas. He was a member of the Texas Senate from the 19th district. Watson served as the acting governor of Texas for one day, on January 9, 1915, when he was the president pro tempore of the Texas Senate, after lieutenant governor William Harding Mayes had resigned, and Governor Oscar Branch Colquitt was in Louisiana. He also was the acting Lieutenant Governor of Texas.