Sir Peter George Snell KNZM OBE (17 December 1938 – 12 December 2019) was a New Zealand middle-distance runner. He won three Olympic gold medals, and is the only man since 1920 to have won the 800 and 1500 metres at the same Olympics, in 1964.

Snell had a relatively short career as a world-famous international sportsman, 1960–1965, yet achieved so much that he was voted New Zealand's "Sports Champion of the (20th) Century" and was one of 24 inaugural members of the International Association of Athletics Federations Hall of Fame named in 2012. A protégé of the New Zealand athletics coach Arthur Lydiard, Snell is known for the three Olympic and two Commonwealth Games gold medals he won, and the several world records he set.

Born in Ōpunake, Snell moved with his family to Waikato in 1949 where he attended Te Aroha College and became an all-around sportsman. He won several middle-distance running events in his hometown of Te Aroha, although some members of his new school lived in Ngāruawāhia. In 1955 he became a boarding student at Mount Albert Grammar School in Auckland, where he took up a wide range of team and individual sports, including rugby union, cricket, tennis, badminton, and golf. As a teenager, Snell excelled in tennis, and pursued the sport through appearances at the Auckland and New Zealand Junior Tennis Championships.

At age 19, Snell was motivated to concentrate seriously on running by the comments of his future coach, Arthur Lydiard, who told him, "Peter, with the sort of speed you've got, if you do the endurance training, you could be one of our best middle-distance runners." During his early career under the tutelage of Lydiard, he started with New Zealand titles and records for 880 yards and the mile, despite being an unusually large and powerful man by typical middle-distance runner standards.

Snell came to international attention with his gold medal in the 800 metres at the Rome Olympics in 1960, setting a new national record. He was particularly dominant four years later at the Tokyo Olympics where he won the gold and set a new Olympic record in the 800 metres, and won gold in the 1500 metres.

By winning the 800–1500 m double, Snell became only the second male to achieve this feat at the Olympics after Albert Hill in 1920, and it has not been achieved by any male athlete at the Olympics since. It was not achieved by a male at an open global championship until Moroccan-born Rashid Ramzi of Bahrain won both golds at the World Championships in 2005 at Helsinki. (After the 2008 Olympic Games, Ramzi was stripped of his Olympic gold medal for doping, but that penalty was not applied retroactively to his World Championship gold medals.)

In early 1962, Snell lowered the world mile record by a tenth of a second at Cooks Gardens in Whanganui on 27 January, and one week later set new world records for both the 800 m and 880 yards (804.7 m) at Christchurch. He then won gold and set a new record for 880 yd at the Commonwealth Games in Perth in 1962, and won gold for the mile at those same games. In all, Snell set five individual world records and joined fellow New Zealand athletes to set a new four by one mile relay record as well.

Snell's 800 m time of 1:44.3, set on 3 February 1962, remained the world record until Marcello Fiasconaro ran 1:43.7 on 27 June 1973. It was the Oceania area record until Joseph Deng ran 1:44.21 on 20 July 2018. It was also the oldest national record recognised by the IAAF for a standard track and field event, lasting for 62 years until James Preston ran 1:44.04 on 25 May 2024, five years after Snell's death. His time remains the fastest ever run over that distance on a grass track.