John Leonard

John or Jack Leonard may refer to:


 * John Leonard (songwriter), early 19th century radical poet and songwriter, probably born in Gateshead
 * John Leonard (critic) (1939–2008), American literary, television, film, and cultural critic
 * John Leonard (poet) (born 1965), Australian poet
 * John Leonard (Gaelic footballer) (born 1976), Gaelic footballer
 * John Leonard (canoeist) (born 1948), New Zealand sprint canoeist
 * John Leonard (judge) (1926–2002), British judge
 * Johnny Leonard (1903–1995), Australian rules footballer
 * John B. Leonard (1864–1945), American civil engineer
 * John J. Leonard, American roboticist and professor at MIT
 * Jack Leonard (footballer) (1876–?), English footballer
 * Jack Leonard (hurler) (1873–1938), Irish hurler
 * Jack E. Leonard (1910–1973), American comedian and actor
 * John E. Leonard (1845–1878), United States Representative from Louisiana
 * J. William Leonard, director of the Information Security Oversight Office
 * John Leonardi (1541–1609), Catholic saint whose feast day is on 9 October
 * John Leonard (bishop) (1829–1908), Irish bishop
 * John W. Leonard (1890–1974), US Army general
 * John Leonard, Baron Leonard (1909–1983), British Labour Party politician
 * John Leonard (ice hockey), (born 1998), American ice hockey player
 * John Leonard (architect), English architect