Football •
William Clarke (footballer, fl. 1897–1900), English football forward with Lincoln City in the late 1890s •
William Clarke (footballer, born 1909) (1909–?), for Bradford City •
Bill Clarke (Australian footballer) (1882–1945), Australian rules footballer •
Bill Clarke (Canadian football) (1932–2000), Canadian football defensive lineman •
Bill Clarke (football manager), English
Carlisle United F.C. manager, 1933–1935 •
Bill Clarke (footballer, born 1880) (1880–?), English footballer with Sheffield United, Northampton Town and Southampton •
Bill Clarke (footballer, born 1916) (1916–1986), English footballer with Leicester City, Exeter and Southampton •
Willie Clarke (footballer) (1878–1940), Scottish footballer •
Billy Clarke (footballer, born 1987), Irish footballer
Cricket •
William Clarke (cricketer, born 1798) (1798–1856), English cricketer and team manager •
William Grasett Clarke (1821–1893), English cricketer •
William Clarke (Barbadian cricketer) (1841–1907), Barbadian cricketer •
William Clarke (cricketer, born 1846) (1846–1902), English cricketer •
William Clarke (cricketer, born 1849) (1849–1935), English cricketer
Other sports •
Boileryard Clarke (William Jones Clarke, 1868–1959), American Major League Baseball player •
William Clarke (athlete) (1873–?), British Olympic runner •
Will Clarke (cyclist) (born 1985), Australian road cyclist •
Will Clarke (triathlete) (born 1985), British triathlete • Bill Clarke (died 2018), British professional wrestler, best known as the masked
King Kendo ==Science==