William, Willie, Bill, or Billy Thomas may refer to:
Academics W. I. Thomas (William Isaac Thomas, 1863–1947), American sociologist William Jenkyn Thomas (1870–1959), Welsh headmaster and author William Davies Thomas (1889–1954), Welsh literary scholar William G. Thomas III (born 1964), American historian William Thomas (historian) (1936–2025), British historian C. William Thomas, American accounting academic
Arts and entertainment Literature William Moy Thomas (1828–1910), English journalist, literary editor and novelist William Thomas (Islwyn) (1832–1878), Welsh poet William Thomas (Gwilym Marles) (1834–1879), Welsh poet William Hannibal Thomas (1843–1935), American teacher, journalist, judge, writer and legislator William Beach Thomas (1868–1957), British author and journalist William F. Thomas (1924–2014), American newspaper editor
Performing arts William C. Thomas (1903–1984), American film producer Willie B. Thomas (1912–1977), American blues musician Bill Thomas (costume designer) (1921–2000), American costume designer Billie "Buckwheat" Thomas (William Thomas Jr., 1931–1980), American actor Willie Thomas (trumpeter) (1931–2019), American jazz trumpeter and educator William Thomas Jr. (1947–2020), American actor Bill Thomas (actor) (born 1952), English actor Billy Thomas (drummer) (born 1953), American drummer with McBride & the Ride William Thomas (actor) (), Welsh actor Billie Geter Thomas (William Bryan Geter Thomas, 1902–1962), American educator and actress
Visual arts William Thomas (architect) (1799–1860), Anglo-Canadian architect William Tutin Thomas (1829–1892), Anglo-Canadian architect Bill Thomas (American writer, born 1934) (1934–2009), American author and photojournalist
Business and industry William Bevil Thomas (1757–1825), Newfoundland merchant and land developer William Kyffin Thomas (1821–1878), Australian newspaper proprietor William Luson Thomas (1830–1900), British wood-engraver and newspaper proprietor William Thomas (miller) (1838–1891), Australian flour mill industrialist William Winstead Thomas (1848–1904), American insurance company president and architect Sir William James Thomas, 1st Baronet (1867–1945), Welsh industrialist and philanthropist Bill Thomas (businessman) (born 1959), British business executive
Law and politics Australia William Thomas (Australian settler) (1793–1867), Australian colonist William Thomas (Victorian politician) (1869–1924), Victorian politician William Lemen Thomas (1872–1921), Western Australian politician Bill Thomas (Australian politician) (born 1950), Western Australian politician
UK William Thomas (MP for Old Sarum and Downton) (died 1554), Welsh MP for Old Sarum and Downton William Thomas (MP for Caernarvonshire) (died 1586), English politician, MP for Caernarvonshire, 1574–86 William Thomas (MP for Carnarvon) (died 1653), Welsh politician William Thomas (MP for Ludgershall) (1630–1686), English lawyer and politician Sir William Thomas, 1st Baronet (1641–1706), English politician Sir William Thomas, 2nd Baronet (died 1777), a Thomas baronet of Yapton Sir William Thomas, 4th Baronet (1777–1850), a Thomas baronet of Yapton Sir William Thomas, 5th Baronet (1807–1867), a Thomas baronet of Yapton Russell Thomas (politician) (William Stanley Russell Thomas, 1896–1957), British politician
US W. C. E. Thomas (William C. E. Thomas, 1818–1876), American civic leader William H. Thomas (Wisconsin politician) (1821–1898), American politician William W. Thomas Jr. (1839–1927), American diplomat and politician from Maine William H. Thomas (Alabama judge) (1867–1945), associate justice of the Alabama Supreme Court William H. Thomas (Maryland judge) (c. 1861–1924), judge of the Maryland Court of Appeals William Hannibal Thomas (1843–1935), American teacher, journalist, judge, writer and legislator William Reuben Thomas (1866–1943), American civic leader W. Aubrey Thomas (1866–1951), US representative from Ohio William M. Thomas (), African-American politician in South Carolina William D. Thomas (1880–1936), American politician William Kernahan Thomas (1911–2001), American judge William Henry Thomas (1920–2009), American politician from Maryland Bill Thomas (Montana politician) (born 1935), American politician in Montana House of Representatives Bill Thomas (born 1941), US representative from California Bill Thomas (American writer, born 1943), American legal and political author Bill Thomas (Alaska politician) (born 1947), American politician in Alaska House of Representatives William L. Thomas (born 1967), American jurist
Elsewhere William Fitz Thomas (), Irish judge William Thomas (Newfoundland politician) (1785–1863), Newfoundland politician William Howell Arthur Thomas (1895–1979), Canadian MP
Military William ap Thomas (died 1445), Welsh soldier and sheriff William Holland Thomas (1805–1893), American Confederate army officer William Nathaniel Thomas (1892–1971), US Navy Chief of Chaplains William Bain Thomas (1898–1967), British Army officer William Garfield Thomas Jr. (1916–1942), American naval officer William Waffle Thomas (1919–2014), American air force officer, former Air Force One pilot William H. Thomas (Medal of Honor) (1923–1945), American soldier
Religion William Thomas (bishop of Worcester) (1613–1689), Welsh Anglican bishop of Worcester William Thomas (antiquary) (1670–1738), English Anglican priest and antiquary William Thomas (chancellor of Llandaff Cathedral) (1734–1799), Welsh Anglican priest and scholar William Griffith Thomas (1861–1924), English Anglican priest and theologian William Jones Thomas (1811–1886), Welsh Anglican priest William M. M. Thomas (1878–1951), American Episcopal bishop of the Missionary District of Brazil William Nathaniel Thomas (1892–1971), American Methodist minister and US Navy Chief of Chaplains William S. Thomas (1901–1986), American Episcopal suffragan bishop of the Diocese of Pittsburgh William Thomas (archdeacon of Northumberland) (1927–2020), English Anglican priest Bill Thomas (priest) (born 1943), British Anglican archdeacon of Llandaff
Sports American football William A. Thomas (1948–2019), American football coach Bill Thomas (American football) (born 1949), American football player Willie Thomas (Canadian football) (born 1955), Canadian football player William Thomas (linebacker) (born 1968), American football player Tra Thomas (William Thomas III, born 1974), American football player
Association football (soccer) William Thomas (footballer, born 1885) (1885–?), English soccer player Billy Thomas (footballer, born 1903) (1903–1992), Welsh footballer Bill Thomas (New Zealand footballer) (), New Zealand footballer
Australian rules football Bill Thomas (Australian footballer) (1886–1974), Australian rules footballer William "Digger" Thomas (1890–1953), Australian rules footballer Billy Thomas (Australian footballer) (1902–1968), Australian rules footballer Bill Thomas (footballer, born 1930), Australian rules footballer
Rugby Willie Thomas (rugby union) (1866–1921), Welsh rugby union footballer William Llewellyn Thomas (1872–1943), Welsh rugby union footballer Willie Thomas (rugby league) (1881–1963), Welsh rugby league footballer Billy Thomas (rugby league) (1907–1972), Welsh rugby league footballer Billy Thomas (rugby union) (1933–2013), Welsh rugby union player
Other sports Bill Thomas (baseball) (1877–1950), American baseball player Bill Thomas (sailor) (1918–1982), Canadian sailor Will Thomas (bowls) (William Thomas, born 1954), Welsh lawn and indoor bowler William Thomas (cricketer) (born 1960), English cricketer William Thomas (karateka) (born 1965), English karateka William Godfrey Thomas (1915–1982), Australian rower and rowing coach Billy Thomas (basketball) (born 1975), American basketball player Bill Thomas (ice hockey) (born 1983), American ice hockey player Will Thomas (basketball) (William Thomas, born 1986), American basketball player Bill Thomas (basketball) (1931–2023), American college basketball player and coach Bill Thomas (cricketer) (1921–2000), English cricketer and schoolmaster
Others William Thelwall Thomas (1865–1927), Welsh surgeon Wilhelm Meyer (Adolph Beck case) (a.k.a. William Thomas, ), gained notoriety in Adolph Beck case William Thomas (activist) (1947–2009), American anti-nuclear activist William H. Thomas (physician) (born 1959), American physician
See also Will Thomas (disambiguation) William Thomas Jr. (disambiguation)