William Collins may refer to:

• William Collins (poet) (1721–1759), English poet
• William Collins (painter) (1788–1847), English landscape artist
• William Lucas Collins (1815–1887), English author and clergyman of the Church of England
• William Wiehe Collins (1862–1951), English architectural and landscape genre painter
• Billy Collins (born 1941), American poet
• William P. Collins, author of works on the Bábí and Bahá’í Faiths, see Bahá'í Faith in Europe

• William Collins (Roundhead), English politician who sat in the House of Commons from 1654 to 1659
• William Collins (Warwick MP) (died 1859), Member of Parliament (MP) for Warwick 1837–52
• William Collins (South African politician) (1803–1876), member Volksraad of the Orange Free State
• William Collins (New York politician) (1818–1878), U.S. congressman from New York
• William Whitehouse Collins (1853–1923), New Zealand Member of Parliament for Christchurch in the South Island
• William Collins (English surgeon) (1859–1946), British surgeon and Liberal Party politician
• William Collins (New Zealand surgeon) (1853–1934) sportsman, surgeon, and member of the New Zealand Legislative Council
• William A. Collins (1935–2022), American politician, state representative and mayor from Norwalk, Connecticut
• William T. Collins, American politician, former acting mayor of New York City

• William Collins (publisher) (1789–1853), Scottish founder of the William Collins, Sons publishing house
• William Collins (Lord Provost) (1817–1895), Scottish temperance movement activist; son of publisher William Collins.
• William Collins, Sons (est. 1819), Scottish publishing house, became part of HarperCollins in 1990, a subsidiary of News Corp.
• William Collins (imprint), a non-fiction publishing brand launched by HarperCollins in 2014

• William Collins (cricketer, born 1837) (1837–1876), Australian cricketer
• William Collins (cricketer, born 1848) (1848–1932), Welsh author and cricketer
• William Collins (cricketer, born 1868) (1868–1942), English cricketer
• William Collins (tennis), British tennis player from the 1920s and 30s, see 1930 Wimbledon Championships – Men's Singles
• William Collins (canoeist) (1932–1993), Canadian canoer who competed in the 1956 Summer Olympics
• Bill Collins (athlete) (born 1950), American sprinter
• Billy Collins Jr. (1961–1984), American professional boxer

• William Collins (colonist) (1756–1819), English naval officer and early settler in Tasmania, Australia
• William O. Collins (1809–1880), commandant of Fort Laramie, Wyoming; namesake of Fort Collins, Colorado and Camp Collins
• William Collins (bishop) (1867–1911), Bishop of Gibraltar in the Church of England
• William Henry Collins (1878–1937), Canadian geologist
• William Floyd Collins (1887–1925), American cave explorer
• William J. Collins (1896–1970), president of St. Ambrose University
• William R. Collins (1913–1991), United States Marine Corps general
• William Erle Collins (1929–2013), American parasitologist
• Bootsy Collins (William Earl Collins, born 1951), American funk bassist, singer and songwriter
• Mr William Collins, a fictional character in the Jane Austen novel Pride and Prejudice

• Bill Collins (disambiguation)