Companion of the Most Honourable Order of the Bath, 1864[1] Order of Saint John, Knight of Grace Crimea Medal with Alma, Balaklava, Sebastopol clasps Indian Mutiny Medal New Zealand War Medal Ashantee Medal with Coomassie clasp Legion of Honour (5th Class) Surgeon-General Sir William Alexander Mackinnon KCB QHS (27 June 1830 – 28 October 1897) was Director-General of the British Army Medical Service (1889–1896).

Mackinnon was born in Strath, Isle of Skye, Scotland.

Afterwards he served as assistant professor of surgery at Netly (1866–73); Senior Medical Officer of Sir Garnet Wolseley's Ashanti Force (1873–74); Principal Medical Officer at Aldershot, Colchester, Hong Kong, and at Malta (1874–82); Head of the medical Branch of the Director-General's Office in London (1882–87); and Principal Medical Officer at Gibraltar (1887–89).

[3][4] After being knighted in the 1891 Birthday Honours,[5] Mackinnon served as an Honorary Surgeon to the Queen (QHS).

[3] Mackinnon retired on 7 May 1896 and died next year in London.