John (Jack) Patrick Kirwan (31 March 1896 – 20 October 1968) was a rugby union and rugby league player. He represented the Hawke's Bay province and Auckland in rugby union before switching to rugby league in 1924. He was selected for the New Zealand team in 1925 becoming Kiwi number 174 in the process. His grandson was also named John Kirwan and he went on to become a famous All Black in the 1980s and 90s before also switching to rugby league.