Thomas Ainslie Young (June 12, 1797 – February 8, 1860) was an official and political figure in Lower Canada.
He was born in Quebec City in 1797, the son of John Young (seigneur) and grandson of Thomas Ainslie (colonial official), and studied in Lower Canada and in London.
In 1838, he arrested the editor and printer for Le Canadien, a newspaper viewed as inflammatory.
He arrested a number of other individuals suspected of being involved in rebel activity during the Lower Canada Rebellion; most were released without being charged some time later.
Young also served in the militia, becoming major, and was a director of the Royal Institution for the Advancement of Learning.