Sir William MacCormac, 1st Baronet, KCB, KCVO (17 January 1836 – 4 December 1901) was a notable British surgeon during the nineteenth and early twentieth centuries. MacCormac was a strong advocate of the antiseptic surgical methods proposed by Joseph Lister and he served in conflicts such as the Boer War. An advocate and pioneer of the Royal Army Medical Corps, MacCormac was perhaps the most decorated surgeon in Britain and he served as Serjeant Surgeon to Edward VII.