William or Will Evans may refer to:
- William Evans (British Army officer), British Army officer during the War of Spanish Succession
- William David Evans (1767–1821), English lawyer
- William Evans (1788–1856), British MP for North Derbyshire
- William F. Evans (1799–1865), Texan politician
- Sir William Evans, 1st Baronet (1821–1892), British Liberal politician and benefactor
- William Evans (Pennsylvania politician) (1831–1905), American politician from Pennsylvania
- William Henry Evans (1842–1923), Wisconsin legislator
- William Evans (judge) (1846/7–1918), Welsh judge and legal author
- William D. Evans (1852–1936), jurist in the state of Iowa
- William Evans (Medal of Honor) (1853–1893), American Indian Wars soldier
- William Evans (Australian politician) (1856–1914), Australian union leader and politician
- William Sanford Evans (1869–1950), Manitoba politician
- William E. Evans (politician) (1877–1959), U.S. Congressman from California
- William S. Evans (1884–1984), Lithuanian-born Jewish-American lawyer, politician, and judge
- William Wadsworth Evans (1886–1972), politician in the New Jersey General Assembly
- William Evans (trade unionist) (1899–1983), British trade union leader
- William W. Evans Jr. (1921–1999), American politician in the New Jersey General Assembly
- William J. Evans (general) (1924–2000), United States Air Force general
- William T. Evans (politician) (1925–1991), American politician and judge
- William Andrew Evans (born 1939), British general
- William Evans (ornithologist) (1851–1922), Scottish naturalist, ornithologist and actuary
- William Percival Evans (1864–1959), New Zealand chemistry academic
- William Harry Evans (1876–1956), lepidopterist
- William Evans (cardiologist) (1895–1988), Welsh cardiologist and publisher
- William Evans, Baron Energlyn (1912–1985), Welsh geologist and life peer
- William J. Evans (chemist), American chemist
- William Frederick Evans, Victorian era British entomologist
- William E. Evans (pharmacist), American pharmacist and researcher
- William Eugene Evans (1930–2010), marine mammal acoustician and ecologist
- William Charles Evans (1911–1988), biochemist
- William Evans (baseball), Negro league baseball player
- William Evans (cricketer, born 1883) (1883–1913), South African-born English all-round cricketer
- William Evans (cricketer, born 1897) (1897–1966), English first-class cricketer and civil servant
- William Evans (footballer) (1853–1919), Welsh international football defender
- Will Evans (footballer, born 1991), English football defender
- Will Evans (footballer, born 1997), Welsh football forward
- William W. Evans (1908–1963), American lacrosse player
- William Evans (Australian sportsman) (1876–1964), Queensland cricketer and rugby union player
- William Evans (rugby union, born 1883) (1883–1946), Welsh international rugby union player
- William Evans (rugby union, born 1892) (1892–1979), Welsh rugby union player
- Will Evans (rugby union) (born 1997), English rugby union flanker