Duddy is a surname. Notable people with the surname include:
Brendan Duddy (1936–2017), businessman from Derry, Northern Ireland, who played a key role in the Northern Ireland peace process John Duddy (born 1979), Irish middleweight professional boxer Patrick Duddy, the United States Ambassador to Venezuela Sammy Duddy (1945–2007), became a leading member of the Ulster Political Research Group
See also Fuddy-duddy, person who is fussy while old-fashioned, traditionalist, conformist, or conservative The Apprenticeship of Duddy Kravitz (book), 1959 novel by Mordecai Richler The Apprenticeship of Duddy Kravitz (film), 1974 Canadian comedy-drama film based on the novel Duddy, a 1984 musical based on the Mordecai Richler novel