Jack Whittier Barnes (born 1940) is an American Communist and the National Secretary of the Socialist Workers Party. Barnes was elected the party's national secretary in 1972, replacing the retiring Farrell Dobbs. He had joined the SWP in the early 1960s as a student at Carleton College in Minnesota and quickly became a leading member of the party's youth wing. Barnes was one of a group of members, many of whom also attended Carleton College or other universities, who joined the SWP shortly after the Cuban Revolution. Barnes was a key advocate of the party's 'Turn to Industry' in the 1970s, its exit from the Fourth International in the 1980s and its orientation towards the Cuban Communist Party in the 1990s.