General Sir William Henry Mackinnon, GCB, KCVO (15 December 1852 – 17 March 1929) was a British Army General during World War I. Henry Mackinnon was born in London on 15 December 1852.

[2] After the outbreak of the Second Boer War in October 1899, a corps of imperial volunteers from London was formed in late December 1899.

It proceeded to South Africa in January 1900, returned in October the same year, and was disbanded in December 1900.

He was invested as a Commander of the Royal Victorian Order (CVO) on 11 August 1902.

[2] He was appointed General Officer Commanding-in-Chief for Western Command in 1910; he retired in 1916.