The 100 metres, or 100-meter dash, is a sprint race in track and field competitions. The shortest common outdoor running distance, the 100-meter (109.36 yd) dash is one of the most popular and prestigious events in the sport of athletics. It has been contested at the Summer Olympics since 1896 for men and since 1928 for women. The inaugural World Championships were in 1983.
 The reigning 100 m Olympic or world champion is often named "the fastest man or woman in the world". Noah Lyles and Sha'Carri Richardson are the world champions; Marcell Jacobs and Elaine Thompson-Herah are the men's and women's Olympic champions.
 On an outdoor 400-metre running track, the 100 m is held on the home straight, with the start usually being set on an extension to make it a straight-line race. There are three instructions given to the runners immediately before and at the beginning of the race: "on your marks", "set", and the firing of the starter's pistol. The runners move to the starting blocks when they hear the 'on your marks' instruction. The following instruction, to adopt the 'set' position, allows them to adopt a more efficient starting posture and isometrically preload their muscles: this will help them to start faster. A race-official then fires the starter's pistol to signal the race beginning and the sprinters stride forwards from the blocks. Sprinters typically reach top speed after somewhere between 50 and 60 m. Their speed then slows towards the finish line.
 The 10-second barrier has historically been a barometer of fast men's performances, while the best female sprinters take eleven seconds or less to complete the race. The current men's world record is 9.58 seconds, set by Jamaica's Usain Bolt in 2009, while the women's world record is 10.49 seconds set by American Florence Griffith-Joyner in 1988.
 At the start, some athletes play psychological games such as trying to be last to the starting blocks.
 At high level meets, the time between the gun and first kick against the starting block is measured electronically, via sensors built in the gun and the blocks. A reaction time less than 0.1 s is considered a false start. The 0.2-second interval accounts for the sum of the time it takes for the sound of the starter's pistol to reach the runners' ears, and the time they take to react to it.
 For many years a sprinter was disqualified if responsible for two false starts individually. However, this rule allowed some major races to be restarted so many times that the sprinters started to lose focus. The next iteration of the rule, introduced in February 2003, meant that one false start was allowed among the field, but anyone responsible for a subsequent false start was disqualified.
 This rule led to some sprinters deliberately false-starting to gain a psychological advantage: an individual with a slower reaction time might false-start, forcing the faster starters to wait and be sure of hearing the gun for the subsequent start, thereby losing some of their advantage. To avoid such abuse and to improve spectator enjoyment, the IAAF implemented a further change in the 2010 season – a false starting athlete now receives immediate disqualification. This proposal was met with objections when first raised in 2005, on the grounds that it would not leave any room for innocent mistakes. Justin Gatlin commented, "Just a flinch or a leg cramp could cost you a year's worth of work." The rule had a dramatic impact at the 2011 World Championships, when current world record holder Usain Bolt was disqualified.
 Runners usually reach their top speed just past the halfway point of the race and progressively decelerate to the finish. Maintaining that top speed for as long as possible is a primary focus of training for the 100 m. Pacing and running tactics do not play a significant role in the 100 m, as success in the event depends more on pure athletic qualities and technique.
 The winner, by IAAF Competition Rules, is determined by the first athlete with their torso (not including limbs, head, or neck) over the nearer edge of the finish line. There is therefore no requirement for the entire body to cross the finish line. When the placing of the athletes is not obvious, a photo finish is used to distinguish which runner was first to cross the line.
 Climatic conditions, in particular air resistance, can affect performances in the 100 m. A strong head wind is very detrimental to performance, while a tail wind can improve performances significantly. For this reason, a maximum tail wind of 2.0 metres per second (4.5 mph) is allowed for a 100 m performance to be considered eligible for records, or "wind legal".
 Furthermore, sprint athletes perform a better run at high altitudes because of the thinner air, which provides less air resistance. In theory, the thinner air would also make breathing slightly more difficult (due to the partial pressure of oxygen being lower), but this difference is negligible for sprint distances where all the oxygen needed for the short dash is already in the muscles and bloodstream when the race starts. While there are no limitations on altitude, performances made at altitudes greater than 1000 m above sea level are marked with an "A".
 The 10-second mark had been widely considered a barrier for the 100 metres in men's sprinting. The first man to break the 10 second barrier with automatic timing was Jim Hines at the 1968 Summer Olympics. Since then, over 180 sprinters have run faster than 10 seconds.
 Major 100 m races, such as at the Olympic Games, attract much attention, particularly when the world record is thought to be within reach.
 The men's world record has been improved upon twelve times since electronic timing became mandatory in 1977. The current men's world record of 9.58 s is held by Usain Bolt of Jamaica, set at the 2009 World Athletics Championships final in Berlin, Germany on 16 August 2009, breaking his own previous world record by 0.11 s. The current women's world record of 10.49 s was set by Florence Griffith-Joyner of the US, at the 1988 United States Olympic Trials in Indianapolis, Indiana, on 16 July 1988 breaking Evelyn Ashford's four-year-old world record by .27 seconds. The extraordinary nature of this result and those of several other sprinters in this race raised the possibility of a technical malfunction with the wind gauge which read at 0.0 m/s- a reading which was at complete odds to the windy conditions on the day with high wind speeds being recorded in all other sprints before and after this race as well as the parallel long jump runway at the time of the Griffith-Joyner performance. All scientific studies commissioned by the IAAF and independent organisations since have confirmed there was certainly an illegal tailwind of between 5 m/s – 7 m/s at the time. This should have annulled the legality of this result, although the IAAF has chosen not to take this course of action. The legitimate next best wind legal performance would therefore be Elaine Thompson-Herah's 10.54 second clocking in 2021 at the Prefontaine Classic. Griffith-Joyner's next best legal performance of 10.61 from 1988, would have her third on the all-time list behind Thompson-Herah and Shelly-Ann Fraser-Pryce (10.60).
 Some records have been marred by prohibited drug use – in particular, the scandal at the 1988 Summer Olympics when the winner, Canadian Ben Johnson was stripped of his medal and world record.
 Jim Hines, Ronnie Ray Smith and Charles Greene were the first to break the 10-second barrier in the 100 m, all on 20 June 1968, the Night of Speed. Hines also recorded the first legal electronically timed sub-10 second 100 m in winning the 100 metres at the 1968 Olympics. Bob Hayes ran a wind-assisted 9.91 seconds at the 1964 Olympics.
 Updated 29 July 2023
 As of September 2023
 Any performance with a following wind of more than 2.0 metres per second is not counted for record purposes. Below is a list of wind-assisted times (equal or superior to 9.80). Only times that are superior to legal bests are shown:
 As of September 2023
 Any performance with a following wind of more than 2.0 metres per second is not counted for record purposes. Below is a list of wind-assisted times (equal or superior to 10.75). Only times that are superior to legal bests are shown:
 Notes:
  
 Updated July 2023
 Below is a list of all other legal times equal or superior to 10.06:
 Updated June 2023
 Below is a list of all other legal times equal or superior to 11.10:
 Updated June 2023
 Below is a list of all other legal times equal or superior to 10.20:
 Updated June 2023
 Below is a list of all other legal times equal or superior to 11.24:
 The best performances by 5- to 19-year-old athletes 
  
 Updated July 2023
 Updated October 2023