Brigadier-General Sir "Hay" Frederick Donaldson KCB (7 July 1856 – 5 June 1916) was an Australia-born English mechanical engineer. He was born at Sydney, New South Wales, Australia, son of Sir Stuart Alexander Donaldson, the first Premier of New South Wales. He was educated at Eton College, Trinity College, Cambridge, University of Edinburgh and Zurich University. On 15 July 1884, he married Selina Beresford (1859–1938), daughter of Colonel Francis Beresford MP. They had three children.