William Leonard

William or Bill Leonard may refer to:

Government

 * William Leonard (English politician) (fl. 1597), MP for Dover
 * William Leonard (Scottish politician) (1887–1969), MP for Glasgow St. Rollox, 1931–1950
 * J. William Leonard, director of the Information Security Oversight Office
 * Bill Leonard (politician) (born 1947), American politician in California
 * Billy Leonard (born 1955), Irish republican politician

Military

 * William Leonard (Medal of Honor), Medal of Honor recipient during the Plains Indian Wars
 * William E. Leonard (1836–1891), Medal of Honor recipient in the American Civil War
 * William F. Leonard (1913–1985), recipient of the Medal of Honor
 * William N. Leonard (1916–2005), American World War II flying ace and United States Navy admiral

Others

 * William Andrew Leonard (1848–1930), American author and prelate of the Episcopal Church
 * William Ellery Leonard (1876–1944), American poet
 * William J. Leonard (1927–2006), American football player
 * William Robert Leonard or Bobby Leonard (1932–2021), American basketball player and coach
 * Bill Leonard (journalist) (1916–1994), American broadcast journalist
 * Bill J. Leonard (born 1946), American historian of religion