Brigadier-General Sir Harry Osborne Mance, KBE, CB, CMG, DSO (2 October 1875 – 30 August 1966) was a senior British Army officer during the First World War, transportation expert and author.

He received his first commission as a second lieutenant in the Royal Engineers in March 1895, was promoted to lieutenant on 15 March 1898,[1] and served during the Second Boer War, between 1899 and 1902, as Deputy Assistant Director of Railways and Armoured Trains on the Kimberley line.

He stayed in South Africa throughout the war, which formally ended in June 1902 after the Peace of Vereeniging, and left Cape Town for home on the SS Britannic in early October that year.

He was author of reports on Austrian Federal Railways, in 1933, and on the co-ordination of transportation in East Africa, in 1936.

His elder son, Henry Stenhouse Mance, became chairman of Lloyd's of London.