General Sir Gordon Holmes Alexander MacMillan of MacMillan and Knap, KCB, KCVO, CBE, DSO, MC & Two Bars (7 January 1897 – 21 January 1986) was a professional soldier who rose to become a general in the British Army. As a young officer during the First World War, he displayed outstanding bravery and was awarded a Military Cross and two Bars. At the age of 19 and while still a second lieutenant, he was appointed acting adjutant of the 2nd Battalion, Argyll and Sutherland Highlanders. Between the World Wars, MacMillan remained in the army, occupying posts of increasing seniority. He married Marian Blakiston Houston in 1929, and they had one daughter and four sons.