John Norman Stuart Buchan, 2nd Baron Tweedsmuir CBE, CD, FRSE, FRSA (25 November 1911 – 20 June 1996), commonly called Johnnie Buchan, was a Scottish peer and the son of the novelist John Buchan, 1st Baron Tweedsmuir.
He was a colonial administrator and naturalist, but also a true-life adventurer.
He has been described as a "brilliant fisherman and naturalist, a gallant soldier and fine writer of English, an explorer, colonial administrator and man of business."