Sir John George Walker, KNZM, CBE (born 12 January 1952) is a former middle-distance runner from New Zealand who won the gold medal in the men's 1500 m event at the 1976 Olympics.

Walker achieved world prominence in 1974 when he finished second to Filbert Bayi of Tanzania in the 1500 metre run at the Commonwealth Games in Christchurch, New Zealand.

Walker also took the bronze medal in the 800 metres in 1:44.92, his lifetime best for the distance; it still ranks him third-fastest New Zealander ever, behind James Preston and Peter Snell.

Coincidentally, Walker's time was exactly 10 seconds faster than Roger Bannister's historic first sub-four-minute mile of 3:59.4, run twenty-one years previously.

In the 1976 New Year Honours, Walker was appointed an Officer of the Order of the British Empire, for services to athletics, especially as the first person to run the mile in less than 3 minutes and 50 seconds.

[citation needed] Steve Cram of Great Britain broke the record by one one-hundredth of a second on 4 August 1985, running 4:51.39 at Budapest, Hungary.

However, Walker was the favourite in the 1500 metres due to the African boycott of the Games, which deprived the event of several strong competitors including Tanzania's Filbert Bayi, his main rival.

He was fading in the last 20 metres but held off Ivo Van Damme of Belgium and Paul-Heinz Wellmann of West Germany to win the gold medal.

In 1985, Walker became the first man in history to run 100 sub-4 minute miles, achieving that feat just before his friend and rival Steve Scott of the United States.

In the 2009 Queen's Birthday Honours, Walker was appointed Knight Companion of the New Zealand Order of Merit, for services to sport and the community.