William Guy (1810–1885) was a British physician and medical statistician.
William Guy may also refer to:
William Guy (dentist) (1859–1950), British pioneer of modern dentistry William Guy (golfer) (born 1966), Scottish professional golfer William Henry Guy (1890–1968), British Labour Party politician William L. Guy (1919–2013), governor of the U.S. state of North Dakota William Ray Guy or Ray Guy (1949–2022), American football player