Thomas Hamlet Harrison (2 April 1864 – 20 June 1944) was an Australian politician who was a Country Party member of the Legislative Assembly of Western Australia from 1914 to 1924.

He was elected to the Kellerberrin Road Board in 1911, and served until 1915, including as chairman for a period of time.

[3] He continued in the position until August 1922, when he resigned to protest the elevation of a Country MP, Richard Sampson, to cabinet (as Colonial Secretary).

At the 1924 state election, he was opposed by Harry Griffiths, a member of the Executive (or Opposition) faction, as well as several other candidates.

He was defeated by a large margin, receiving only 18.9 percent of the first-preference vote as Griffiths was elected in his place.