Billy, Bill, Will, Willie and William Simpson may refer to:
Artists William Simpson (portrait artist) (c. 1818–1872), African American painter and civil right activist William Simpson (Scottish artist) (1823–1899), Scottish war artist and correspondent William Marks Simpson (1903–1958), American sculptor and teacher Will Simpson (comics) (born 1960), Northern Irish comics, film and television storyboard and concept artist
Politicians William Dunlap Simpson (1823–1890), American governor of South Carolina from 1879 William John Simpson (1851–1901), Canadian journalist and political figure in Quebec William T. Simpson (1886–1980), American legislator in New York state William C. Simpson, American Republican mayor of Ashland, Kentucky in 1936 and 1948
Scholars William Simpson (teacher) (before 1790–after 1828), English headmaster, first (1823–1828) to lead Bootham School William John Ritchie Simpson (1855–1931), Scottish physician and specialist in tropical medicine W. Douglas Simpson (1896–1968), Scottish architecture and archaeology lecturer William Kelly Simpson (1928–2017), American professor of Egyptology and archeology William James Simpson (born 1954), Australian-British-American medievalist, a/k/a James Simpson William R. Simpson (born 1966), American researcher in Alaska of snow chemistry William M. R. Simpson (born 1981), British philosopher, winner of Cardinal Mercier Prize
Sportsmen Billy Simpson (jockey) (c. 1840–1873), South Australian rider and trainer Billy Simpson (footballer, born 1878) (1878–1962), English left back and centre half for Sunderland and Lincoln City William Simpson (rugby league) (before 1890–after 1911), English wing during 1900s and 1910s Billy Simpson (footballer, born 1929) (1929–2017), Northern Ireland centre forward Willie Simpson, American fullback in 1961 on List of Pittsburgh Steelers players Bill Simpson (racing driver) (1940–2019), American racecar safety pioneer Bill Simpson (American football) (born 1951), American defensive back Will Simpson (equestrian) (born 1959), American Olympic show jumper William Simpson (cricket umpire) (1915–1967), English cricket umpire
Others William Hood Simpson (1888–1980), American Ninth Army general in Europe during World War II William Gayley Simpson (1892–1991), American white nationalist and author William Simpson (Australian judge) (1894–1966), Australian general and administrator William Simpson (trade unionist) (1920–2001), Scottish political activist Bill Simpson (actor) (1931–1986), Scottish actor Billy Simpson (singer) (born 1987), Indonesian singer-songwriter
Characters Will Simpson, version of 1986's Nuke (Marvel Comics) in TV series Jessica Jones Will Simpson (Ackley Bridge), teacher in 2017 British TV drama