O'Duffy is a surname. Notable people with the surname include:
Eimar O'Duffy (1893-1935), member of the Irish Republican Brotherhood and writer Eoin O'Duffy (1892-1944), Irish Republican Army Chief of Staff, soldier and police commissioner Paul Staveley O'Duffy (born 1963), British music producer Seán O'Duffy (1888-1985), Irish sports administrator of women's camogie
See also Duffy (surname)