Martin James Guptill (born 30 September 1986) is a New Zealand international cricketer who plays as an opening batsman in limited overs formats of the game. Guptill is the first cricketer from New Zealand and the fifth overall to have scored a double century in a One Day International match and holds the current record for the highest individual score in Cricket World Cup matches and the second highest score in One Day Internationals of 237 not out. In March 2021, Guptill played in his 100th T20I match.

Guptill first represented New Zealand in the Under-19 Cricket World Cup held in Sri Lanka in 2006. He made his One Day International (ODI) debut for New Zealand on 10 January 2009 against the West Indies in Auckland, becoming the first New Zealander to score a century on his one-day debut - his score of 122 not out is the highest score on debut for New Zealand in an ODI, and second highest debut score ever in ODIs and he was the first New Zealander to carry the bat through a completed ODI innings. He made his Test cricket debut against India in the first Test at Hamilton in March 2009, scoring 14 and 48. For his performances in 2009, he was named in the World ODI XI by the ICC.