John, Jack, Johnny, Jon, or Jonathan Dunn may refer to:

• John Dunn (pipemaker) (c. 1764–1820), inventor of keyed Northumbrian smallpipes
• John Dunn (actor) born O'Donoghue (1813–1875), Australian comic actor
• John Millard Dunn (1865–1936), organist and choirmaster
• John Dunn (violinist) (1866–1940), English violinist
• Johnny Dunn (1897–1937), American jazz trumpeter
• Jon Dunn (musician), American musician
• John Dunn (software developer) (born 1943), American musician and art software developer
• John Dunn (animator) (1919–1983), cartoon writer for DePatie-Freleng and Looney Tunes
• John W. Dunn (painter) (1891–1975), American painter
• John Dunn (radio presenter) (1934–2004), BBC Radio 2 DJ

• John Henry Dunn (1792–1854), businessman and political figure in Canada West
• John Dunn Jr. (assemblyman) (1827–1909), Wisconsin politician
• John T. Dunn (1838–1907), U.S. Representative from New Jersey
• John Dunn Jr. (1830–1892), South Australia politician
• John Freeman Dunn (1874–1954), English banker and stockbroker, barrister and Liberal Party politician
• John Dunn (1820–1860), British Conservative politician

• John Woodham Dunn (1812–1883), Anglican vicar of Warkworth, Northumberland
• John Joseph Dunn (1870–1933), American prelate of the Catholic Church

• Jack Dunn (baseball) (1872–1928), minor league baseball owner and manager
• John Dunn (cricketer) (1862–1892), English cricketer
• John Dunn (footballer, born 1888) (1888–1968), English football inside right
• John Dunn (footballer, born 1944), English footballer for Aston Villa and Charlton Athletic
• Jack Dunn (footballer, born 1994), English football player
• Johnny Dunn (footballer) (1881–1947), Australian rules footballer for Collingwood
• Jon Dunn (born 1981), American football player
• Jack Dunn (soccer), American soccer player
• Jack Dunn (figure skater) (1917–1938), British figure skater
• John Dunn (Australian rules footballer)
• John Dunn (American football), American football coach and former player
• John Dunn (American football, born 1888), American football player and team owner
• Jack Dunn (rugby union) (1918–2003), New Zealand rugby union player

• John Dunn (miller) (1802–1894), flour miller, parliamentarian, and philanthropist in South Australia
• John Ainsworth Dunn (1831–1915), furniture manufacturer in Massachusetts
• John Robert Dunn (1833–1895), Scottish settler in South Africa
• John Dunn (bushranger) (1846–1866), Australian bush ranger
• John Dunn (explorer) (born 1954), explorer of the Canadian Arctic
• John "Pudgy" Dunn (1896–1937), St. Louis gangster
• John M. Dunn (1910–1949), American mobster, executed in 1949
• John Dunn (political theorist) (born 1940), professor of political theory at the University of Cambridge
• John Dunn (university president) (born 1945), president of Western Michigan University
• John Asher Dunn, American linguist
• John W. Dunn (architect), American architect
• Jon Michael Dunn (1941–2021), American educator
• John Thomas Dunn (chemist) (1858–1939), English chemist

• John Donne (1572–1631), English poet, satirist, lawyer and priest
• John Dunne (disambiguation)
• Dunn (surname)