William Hart, also Will, Willy, Bill, or Billy Hart may refer to:
Arts and entertainment William Hart (actor) (died 1650), English Caroline actor William Hart (painter) (1823–1894), Scottish-American painter William Hart (singer) (1945–2022), American soul singer, member of The Delfonics William Howard Hart (1863–1937), American painter William Matthew Hart (1830–1908), British lithographer and bird artist William S. Hart (1864–1946), American silent film actor, screenwriter, director, and producer William Sterling Hart (1917–2006), American actor, better known as Robert Sterling Will Cullen Hart (1971–2024), American musician and artist Billy Hart (born 1940), American jazz drummer
Judiciary William Hart of Livelands, Scottist jurist and 16th century Lord Advocate William H. H. Hart (died 1918), American California attorney general William L. Hart (1867–1962), American justice of the Supreme Court of Ohio William Thomas Hart (1929-2023), United States federal judge
Sports Bill Hart (footballer) (1923–1990), English professional footballer Bill Hart (infielder) (1913–1968), American professional baseball third-baseman with the Brooklyn Dodgers Bill Hart (pitcher) (1865–1936), American professional baseball pitcher Billy Hart (baseball) (1866–1944), American professional baseball player
Other people William Hart (bishop) (1904–1992), Bishop of Dunkeld William Hart (Medal of Honor) (1866–1899), American sailor William Hart (MP), MP for Bletchingley William Hart (police chief) (1924–2003), Detroit Police Chief William Hart (Tasmanian politician) (1825–1904), Tasmanian businessman William Hart (priest) (1558–1583), Catholic martyr William Hart, drilled the first natural gas well in the US, leading to the Fredonia Gas Light Company's formation William C. Hart (1898–1963), United States Coast Guard member awarded the Gold Lifesaving Medal William E. Hart (1843–1874), Union Army soldier during the American Civil War William Ewart Hart (1885–1943), Australian aviator and dentist William Neville Hart (1741–1804), British banker, politician and diplomat William Stanford Hart Sr. (1925–1999), mayor of East Orange, New Jersey William Henry Harrison Hart (1857–1934), African American attorney and professor of criminal law William H. Hart (1864–1926), United States Army officer
Other uses USCGC William Hart, a Sentinel-class cutter in the United States Coast Guard
Fictional characters Bill Hart (comics), the civilian identity of the Lev Gleason Publications and Image Comics superhero Daredevil