Baron Thomson of Fleet, of Northbridge in the City of Edinburgh, is a title in the Peerage of the United Kingdom. It was created in 1964 for Roy Thomson, a Canadian-born newspaper magnate. He was succeeded in 1976 by his son, the second baron. As of 2020^[update], the title is held by the first Baron's grandson, the third Baron, who succeeded his father in 2006.

The heir to this title is the present holder's son, the Hon. Benjamin James Ludwick Thomson (b. 2006)