William Thomson
William, Billy or Bill Thomson may refer to:
Military
- William Thomson (American soldier), American militia captain in Capture of Savannah
- William Taylour Thomson, British military officer and diplomat
- William Montgomerie Thomson, British general and commander of the British expeditionary force in north Persia
- William McKenzie Thomson, Canadian World War I pilot
Politics
- William Alexander Thomson, Canadian author and politician
- William Thomson (politician), Member of Parliament in Christchurch, New Zealand
- William Mitchell-Thomson, 1st Baron Selsdon, British politician
Religion
- William Thomson (writer), Scottish minister and historian
- William Aird Thomson, Scottish minister and antiquarian
- William McClure Thomson, American missionary and writer
- William Thomson (bishop), Archbishop of York, 1862–1890
- William Burns Thomson, Scottish medical missionary
Science
- William Thomson (mineralogist), English physician and geologist
- William Thomson (physician), Scottish author and professor of medicine
- William Thomson, 1st Baron Kelvin, Scots-Irish mathematician, physicist and engineer.
- William Thomson (surgeon), Irish surgeon
- William Johnston Thomson, Scottish engineer and businessman
Sports
- William Thomson (Dumbarton footballer), Scottish footballer
- William Thomson (Dundee footballer), Scottish footballer
- William Thomson (rugby union), Scottish international rugby union player
- Bill Thomson (cricketer), 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), Scottish goalkeeper for St Mirren, Dundee United, Motherwell, Dundee and Scotland
- Bill Thomson (ice hockey), Canadian ice hockey player
Other
- Edward William Thomson (writer), Canadian writer
- William Thomson (artist), British artist
- William Thomson (musicologist), Scottish folk song collector and singer
- William John Thomson, American artist
- W. H. Seward Thomson, U.S. federal judge
- William Thomson (mathematician), Scottish mathematician
- William Thomas Thomson (actuary), Scottish actuary
- William James Thomson, Canadian artist and engraver
- William Ennis Thomson, music school dean