Lieutenant-General Douglas Mackinnon Baillie Hamilton Cochrane, 12th Earl of Dundonald KCB KCVO (29 October 1852 – 12 April 1935), styled Lord Cochrane between 1860 and 1885, was a Scottish representative peer and a British Army general.
Cochrane was the second but eldest surviving son of Thomas Cochrane, 11th Earl of Dundonald, by Louisa Harriet Mackinnon, daughter of William Alexander Mackinnon. Thomas Cochrane, 1st Baron Cochrane of Cults, was his younger brother. He was educated at Eton College.
Cochrane was commissioned into the Life Guards in 1870. He served in the Nile Expedition the Desert March and the Relief of Khartoum in 1885. He was appointed Commanding Officer of 2nd Life Guards in 1895.
He served in the Second Boer War and in 1899 he was appointed Commander of the Mounted Brigade, part of the South Natal Field Force. He took part in the Relief of Ladysmith in February 1900, although his South African troops, unimpressed by his leadership, referred to him as “Dundoodle”. He was appointed General Officer Commanding the Militia of Canada in 1902. He served in World War I as Chairman of the Admiralty Committee on Smoke Screens in 1915.
He is buried in Achnaba Churchyard, Ardchattan near Benderloch, Lorne, Argyll & Bute.
Dundonald Park, in Centretown, Ottawa, Ontario, is named after him.
He was appointed a Commander of the Royal Victorian Order (CVO) in December 1901, and in June 1907 knighted as a Knight Commander (KCVO) of the order.