Sir Thomas Duncan MacGregor Stout CBE DSO ED (25 July 1885 – 27 February 1979) was a New Zealand medic, soldier and author.
Born in Wellington in 1885, he was the son of Robert Stout, who was the Premier of New Zealand at the time. He was educated at Wellington College and then studied medicine at Guy's Hospital, University of London. He was conferred LRCP in 1910 and received a ChM in 1914.
He married Agnes Isobel Pearce MBE, who served as an ambulance driver at Brockenhurst Hospital in Hampshire during the First World War, at St Paul's in Wellington on 4 December 1919. The couple had four children: Squadron Leader Robert Edward Stout; Arthur Duncan Stout; John David Stout (whose legacy funds the Stout Centre); and Vida Stout.
He saw service in both World War I and World War II and wrote three volumes of the official history of New Zealand in the latter war. He was the first chancellor of Victoria University of Wellington after the dis-establishment of the University of New Zealand into its constituent colleges.