Thomas Williamson, Baron Williamson, CBE (2 September 1897 – 27 February 1983) was a trade unionist and Labour Party politician in the United Kingdom.
He was General Secretary of the National Union of General and Municipal Workers from 1946 to 1961, and President of the Trades Union Congress from 1957 to 1958.
At the 1945 general election, he was elected as Member of Parliament (MP) for the Brigg constituency in Lincolnshire. He resigned his seat in 1948, and the resulting by-election was won by Labour's Lance Mallalieu.
Williamson was appointed a Commander of the Order of the British Empire (CBE) in 1950, and was knighted in 1956.
Williamson was created a life peer on 15 May 1962, with the title Baron Williamson, of Ecccleston in the Borough of St. Helens in the County Palatine of Lancaster.
He died in 1983, aged 85.