William Henry may refer to:
- William Henry (actor) (1914–1982), United States movie actor
- William Henry (agriculturist), agriculturist at the University of Wisconsin (see Single-grain experiment)
- William Henry (brother of Patrick Henry) (1734–1785), representative in the House of Burgesses
- William Henry (chemist) (1774–1836), English chemist who formulated Henry’s law
- William Henry (congressman) (1788–1861), United States Congressman from Vermont
- William Henry (gunsmith) (1729–1786), American gunsmith and Pennsylvania delegate to Continental Congress
- William Henry (swimmer) (1859–1928), British swimmer
- William Henry, Prince of Nassau-Saarbrücken (1718–1768)
- William Henry, Prince of Nassau-Usingen (1684–1718)
- William Alexander Henry (1816–1888), justice of the Canadian Supreme Court
- William A. Henry III (1950–1994), United States author and cultural critic
- William H. Henry, Executive Secretary of the Socialist Party of America during the late 1920s
- William "Jerry" Henry, a fugitive slave in Syracuse, New York in the United States who was arrested and freed in an event known as the Jerry Rescue
- William Thomas Henry (1872–1952), politician in Alberta, Canada and member of the Legislative Assembly of Alberta
- William W. Henry (1831–1915), Medal of Honor recipient
- William Wirt Henry (1831–1900), Virginia lawyer, politician, historian and writer
- Prince William Henry, Duke of Gloucester and Edinburgh (1743–1805), member of the British Royal Family and a younger brother of King George III