World records in the marathon are ratified by World Athletics, the international governing body for the sport of athletics.^{[citation needed]}

Kenyan athlete Kelvin Kiptum set a men's world record time of 2:00:35 on October 8, 2023, at the 2023 Chicago Marathon, a mixed-sex race.

Kenyan athlete Ruth Chepng'etich broke the women's world record with a time of 2:09:56 on October 13, 2024, at the 2024 Chicago Marathon, a mixed-sex race.

In addition to the standard women's marathon world record, World Athletics also recognizes a second world record for women in the "Women Only" category, meaning that the marathon was run on a course without any male athletes in the competition. The current "Women Only" record of 2:15:50 was set by Tigst Assefa on April 27, 2025, at the London Marathon in the elite women's race.

Marathon races were first held in 1896, but the distance was not standardized by the International Association of Athletics Federations (IAAF, now World Athletics) until 1921.

The actual distance for pre-1921 races frequently varied from the 1921 standard of 42.195 km (26 miles 385 yards). In qualifying races for the 1896 Summer Olympics, Greek runners Charilaos Vasilakos (3:18:00) and Ioannis Lavrentis (3:11:27) won the first two modern marathons. On April 10, 1896, Spiridon Louis of Greece won the first Olympic marathon in Athens, Greece, in a time of 2:58:50. However, the distance for the event was 40,000 meters. Three months later, British runner Len Hurst won the inaugural Paris to Conflans Marathon (also around 40 km) in a time of 2:31:30. In 1900, Hurst would better his time on the same course with a 2:26:28 performance.

Later, Shizo Kanakuri of Japan was reported to have set a world record of 2:32:45 in a November 1911 domestic qualification race for the 1912 Summer Olympics, but this performance was also run over a distance of approximately 40 km.

The first marathon over the official distance was won by American Johnny Hayes at the 1908 Summer Olympics, with a time of 2:55:18.4.