William, Billy or Bill Thomson may refer to:
Military William Thomson (American soldier) (1727–1796), American militia captain in Capture of Savannah William Taylour Thomson (1813–1883), British military officer and diplomat William Montgomerie Thomson (1877–1963), British general and commander of the British expeditionary force in north Persia William McKenzie Thomson (1898–1987), Canadian World War I pilot
Politics William Alexander Thomson (1816–1878), Canadian author and politician William Thomson (politician) (1818–1866), member of parliament in Christchurch, New Zealand William Mitchell-Thomson, 1st Baron Selsdon (1877–1938), British politician
Religion William Thomson (writer) (1746–1817), Scottish minister and historian William Aird Thomson (1773–1863), Scottish minister and antiquarian William McClure Thomson (1806–1894), American missionary and writer William Thomson (bishop) (1819–1890), Archbishop of York, 1862–1890 William Burns Thomson (1821–1893), Scottish medical missionary
Science William Thomson (mineralogist) (1760–1806), English physician and geologist William Thomson (physician) (1802–1852), Scottish author and professor of medicine William Thomson, 1st Baron Kelvin (1824–1907), Scots-Irish mathematician, physicist and engineer William Thomson (surgeon) (1843–1909), Irish surgeon William Johnston Thomson (1881–1949), Scottish engineer and businessman
Sports William Thomson (Dumbarton footballer) ( 1891–1901), Scottish footballer (Dumbarton, Scotland) William Thomson (Dundee footballer) (1874–1917), Scottish footballer (Dundee, Bolton Wanderers, Scotland) William Thomson (rugby union) (1880–1942), Scottish international rugby union player William Thomson (rugby union, born 1876), Scottish international rugby union player Bill Thomson (cricketer) (1943–2019), New Zealand cricketer and hockey player Billy Thomson (footballer, born 1895), Scottish football wing half for Bristol Rovers and Leicester City Billy Thomson (footballer, born 1958) (1958–2023), Scottish goalkeeper for St Mirren, Dundee United, Motherwell, Dundee and Scotland Bill Thomson (ice hockey) (1914–1993), Canadian ice hockey player Willie Thomson (c. 1851–?), Scottish golfer
Other William Thomson (artist) (1926–1988), British artist William Thomson (musicologist) (died 1753), Scottish folk song collector and singer William John Thomson (1771–1845), American artist W. H. Seward Thomson (1856–1932), U.S. federal judge William Thomson (mathematician) (1856–1947), Scottish mathematician William Thomas Thomson (actuary) (1813–1883), Scottish actuary William James Thomson (1857–1927), Canadian artist and engraver William Ennis Thomson (1927–2019), music school dean William Erskine Thomson (1875–1962), Scottish architect William Hanna Thomson (1833–1918), American physician and Christian writer William Thomson (silversmith) (1777–1833), American silversmith
See also William Thompson (disambiguation)