Brigadier Morgan John Winthrop O'Donovan, The O'Donovan, MC (2 May 1893 – 28 April 1969) was a senior British Army officer who held the position of O'Donovan of Clan Cahill from 1940 to his death in 1969. He was the son of Morgan William II O'Donovan and Mary Eleanor Barton, and was a descendant in the male line from Donal II O'Donovan, The O'Donovan of Clancahill, who was the last chief of his sept inaugurated in the ancient Gaelic manner, with the White Rod, by his father-in-law MacCarthy Reagh, Prince of Carbery, circa 1584.