The men's 100 metres competition at the 2012 Summer Olympics in London, United Kingdom was held at the Olympic Stadium on 4–5 August 2012. Seventy-four athletes from 61 nations competed. Each nation was limited to 3 athletes per rules in force since the 1930 Olympic Congress. The competition comprised four rounds: a preliminary round for entrants without the minimum qualifying standard, a heats round, followed by three semi-finals of eight athletes each, which then reduced to eight athletes for the final.
Djibouti competed at the 2012 Summer Olympics in London, from July 27 to August 12, 2012. This was the nation's seventh appearance at the Olympics.
Benjamín Manuel Enzema Owono is an Equatorial Guinean athlete. In the 1500 m event at the 2009 World Championships in Berlin, he set a personal best time of 4:13.17. At the 2012 IAAF World Indoor Championships in Istanbul, Enzema set a new national record time in the 800 m with a 1:58.19. Three months later, at the 2012 African Championships in Porto-Novo, Benin, he shaved a further 1.9 seconds off the record, lowering it to 1:56.29.
Athletics at the 2020 Summer Olympics were held during the last ten days of the Games. They were due to be held from 31 July – 9 August 2020, at the Olympic Stadium in Tokyo, Japan. Due to the COVID-19 pandemic, the games were postponed to 2021, with the track and field events set for 30 July – 8 August. The sport of athletics at these Games was split into three distinct sets of events: track and field events, remaining in Tokyo, and road running events and racewalking events, moved to Sapporo. A total of 48 events were held, one more than in 2016, with the addition of a mixed relay event.
Habitam Alemu Bayih is an Ethiopian middle-distance runner specialising in the 800 metres.
Antonio Alkana is a South African hurdler. He competed in the 110 metres hurdles event at the 2015 World Championships in Beijing narrowly missing the semifinals. In addition, he won the gold at the 2015 African Games. He also competed in the men's 110 metres hurdles at the 2020 Summer Olympics.
Filippo Tortu is an Italian sprinter with a personal best in the 100 metres of 9.99, the first Italian in history to break the 10 seconds barrier, and the second fastest Italian in history following Marcell Jacobs. He won the gold medal in 100 metres at the 2017 European U20 Championships and the silver medal at the 2016 World U20 Championships. He ran the anchor leg in the 4×100m relay of the Italian team that won the gold medal at the 2020 Summer Olympics and at the 2024 European Championships, and the silver medal at the 2023 World Athletics Championships.
Didier Kiki is a Beninese Olympic sprinter.
Ned Justeen Azemia is a Seychellois hurdler who specialises in the 400 metres hurdles. He is the current Seychellois record holder in the event. Azemia competed in the 2016 Summer Olympics in Rio de Janeiro in the 400 metres hurdles. He has also competed in two World Junior Championships, an African athletics championships and an African Youth Games. Azemia has also raced over the flat 400 metres distance.
Margaret Vanessa Barrie is a Sierra Leonean sprinter. She competed in the women's 400 metres at the 2017 World Championships in Athletics. In 2019, she competed in the women's 200 metres and women's 4 × 400 metres relay at the 2019 African Games held in Rabat, Morocco.
Lada Vondrová is a Czech track and field athlete who specializes in sprint races. She won several Czech national titles.
Venezuela competed at the 2020 Summer Olympics in Tokyo. Originally scheduled to take place from 24 July to 9 August 2020, the Games were postponed to 23 July to 8 August 2021, due to the COVID-19 pandemic. It was the nation's nineteenth consecutive appearance at the Summer Olympics.
Ebrahima Camara is a Gambian athlete. He competed in the men's 100 metres event at the 2019 World Athletics Championships.
Tomoki Suzuki is a Japanese wheelchair racer, who won the 2020 and 2024 Tokyo Marathons, came second at the 2015, 2018, 2021 and 2023 Tokyo Marathons, and came third at the 2017 Tokyo, 2019 and 2023 London Marathons. Suzuki and won a bronze medal in the mixed 4 × 100 metres relay at the 2020 Summer Paralympics, and a bronze medal in the marathon T54 event at the 2024 Summer Paralympics.
Saint Kitts and Nevis competed at the 2020 Summer Olympics in Tokyo. Originally scheduled to take place from 24 July to 9 August 2020, the event was postponed to 23 July to 8 August 2021, because of the COVID-19 pandemic. This was the nation's seventh appearance at the Summer Olympics since their debut in 1996. The delegation consisted of two athletes, competing in athletic events; Jason Rogers and Amya Clarke. For the first time, in an effort to promote gender equality, two flagbearers, one male and one female were allowed at the Olympics. Both athletes from Saint Kitts and Nevis bore the national flag at the opening ceremony. Saint Kitts and Nevis did not win any medals during the Tokyo Olympics. Rogers ranked third in the first round of the men's 100 metres and advanced to the semifinals where he was eliminated. Clarke also ranked third in her preliminary round of the women's 100 metres and advanced to round 1 where she ranked 7th and was eliminated.
Azreen Nabila binti Alias is a Malaysian athlete.
Pen Sokong is an Olympic sprinter from Cambodia.
Ildar Akhmadiev is an Olympic sprinter from Tajikistan.
Seco Camara is an Olympic sprinter from Guinea-Bissau.
Nathan Maguire is a British wheelchair racer. He won multiple medals at both the 2018 and 2021 World Para Athletics European Championships, and also won the 400 metres mixed class race at multiple British Athletics Championships. Maguire competed in the 4 × 400 metres relay T53/T54 at the 2016 Summer Paralympics, and competed in the 400 metres T54, 800 metres T54 and mixed 4 × 100 metres relay events at the delayed 2020 Summer Paralympics. He was part of the British team that won a silver medal in the 2020 Paralympic mixed 4 × 100 metres relay. He also competed for England at the 2018 Commonwealth Games, and won the 1500 metres T54 event at the 2022 Commonwealth Games.
