There have been a number of people named
William Thomson:
- William Thomson, 1st Baron Kelvin (1824–1907), UK physicist now usually known as Lord Kelvin
- William Thomson, Archbishop of York (1819–1890), Archbishop of York 1862–1890
- William Thomson (musicologist) (fl. 1695–1753), Scottish folk song collector and singer
- William Thomson (ice hockey), Canadian ice hockey player
- William Alexander Thomson, Canadian author and politician
- William John Thomson, Scottish portrait miniature artist.
- Sir William Thomson (Solicitor General), Solicitor General for England and Wales 1717–1720
- William McKenzie Thomson, Canadian WWI pilot
- William P. L. Thomson, Scottish historian
- William Mitchell-Thomson, 1st Baron Selsdon, British politician
- Edward William Thomson, Canadian politician
- Edward William Thomson (writer), Canadian writer
- John William Thomson, Canadian politician
- Robert William Thomson, Scottish inventor of the pneumatic tyreSee also
- William Thompson