Twynam is a surname. Notable people with the surname include:
Henry Twynam (1853–1899), English rugby union international Henry Joseph Twynam (1887–1966), British colonial administrator in India Mervyn Twynam Davis (1916–1985), Australian servicewoman William Crofton Twynam (1827–1922), British colonial administrator in Ceylon
See also Mount Twynam, in New South Wales Twinam, surname