John Jansen may refer to:
Sports John Jansen (rugby league) (born 1955), Australian rugby league footballer John Jansen (water polo) (born 1963), retired water polo player from the Netherlands Jon Jansen (born 1976), American football player
Others John Jansen (politician) (1947–2026), Canadian politician, mayor of Chilliwack and member of British Columbia Legislative Assembly John Jansen (record producer) (born 1947), American recording engineer and music producer
See also John Janssen (1835–1913), German-born American Roman Catholic bishop in Illinois Jonathan Janssen (born 1995), New Zealand basketball player