The 400 metres, or 400-meter dash, is a sprint event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 for men and since 1964 for women. On a standard outdoor running track, it is one lap around the track. Runners start in staggered positions and race in separate lanes for the entire course. In many countries, athletes previously competed in the 440-yard dash (402.336 m)—which is a quarter of a mile and was referred to as the "quarter-mile"—instead of the 400 m (437.445 yards), though this distance is now obsolete.
Marek Plawgo is a Polish athlete. He mainly competes in the 400 meters hurdles, but he also starts in the 400 meters and the 4 x 400 meters relay.
Matthew John "Matt" Elias is a retired Welsh athlete who specialised in the 400 metres sprint and 400 metres hurdles. During his international career he represented Great Britain. In 2003 he won a gold medal at the European Championships and at the 2004 Olympic Games in Athens he finished 5th in the 4 × 400 m relay, He is also a part of Super Schools.
Eilidh Doyle is a retired British track and field athlete. Originally running as Eilidh Child, she specialised in the 400 metres hurdles outdoors, and the 400 metres flat indoors, as well as the 4 x 400 metres relay on both surfaces. She represented Great Britain at the 2012 Olympic Games in London, and won an Olympic bronze medal in the 4 x 400 metres relay at the 2016 Games in Rio de Janeiro. Individually, she is the 2014 European Champion and a three-time Commonwealth silver medalist in the 400 metres hurdles.
Jack Green is a British sprint athlete who specialises in the 400m distance, along with the hurdles and the 4 × 400 m relay. He competed for the Great Britain team at the 2012 Summer Olympics in London and at the 2016 Summer Olympics in Rio de Janeiro.
Vernon Larnard Norwood is an American track and field athlete who specializes in the 400 meters.
Sage Heather Walker is a Canadian athlete specializing in the 400 metres hurdles. Competing internationally for Canada, she is the reigning Pan American champion in the 400 m hurdles, having also won Pan American medals in 2015 and 2019 as part of Canada's relay team.
Laviai Nielsen is a British sprinter specialising in the 400 metres.
Christopher O'Donnell is an Irish track and field athlete competing in sprinting events. He was part of the Irish Mixed 4x400m team who won a gold medal at the 2024 European Athletics Championships. He represented Ireland at the Tokyo 2020 Olympic Games in the Mixed 4 × 400 m relay, where he was part of the first ever Irish team to run in an Olympic final, and competed in the same event at the Paris 2024 Olympic Games. He was also part of the team who reached the final of the 2022 and 2023 World Championships. He is the current Irish U20 record holder in the 400m, his personal best of 45.26 seconds sits joint-2nd on the Irish all-time list and he is a 5-time National 400m champion.
Rhasidat Adeleke is an Irish sprinter.
Shiann Salmon is a Jamaican track and field athlete who specializes in the 400 metres hurdles and 400 metres. She represented Jamaica at the 2019 World Athletics Championships, competing in women's 400 metres hurdles.
Femke Bol is a Dutch track and field athlete who competes in hurdling and sprinting. She specialises in the 400 metres hurdles, where she is the 2023 World Champion, and in the 400 metres, where she is the 2024 World Indoor Champion and the short track world record holder. In the 4 × 400 metres relay, she is the 2023 World Champion and the 2024 World Indoor Champion with the Dutch women's team and the 2024 Olympic Champion with the Dutch mixed team.
Paulien Couckuyt is a Belgian track and field athlete who specializes in middle-distance running and 400 metres hurdles.
Lieke Klaver is a Dutch track and field athlete who competes in sprinting. She specializes in the 200 metres and in the 400 metres. In the 4 × 400 metres relay, she is the 2023 World Champion and the 2024 World Indoor Champion with the Dutch women's team and the 2024 Olympic Champion with the Dutch mixed team.
Alastair Chalmers is a British track and field hurdler who specialises in the 400 metres hurdles. He won Guernsey's first-ever Commonwealth Games track and field medal when he took bronze at the 2022 edition and he is a five-time British 400m hurdles champion.
Sophie Becker is an Irish athlete who competes as in the sprint events and mainly specialises in the 400 m.
Sharlene Mawdsley is an Irish athlete who specialises in the 400 meters and other sprint events.
Cathelijn Peeters is a Dutch track and field athlete who competes in hurdling and sprinting and previously competed in the combined events and hammer throw. Peeters specializes in the 400 metres hurdles and in the 400 metres. In the 4 × 400 metres relay, she is the 2023 World Champion and the 2024 World Indoor Champion with the Dutch women's team and the 2024 Olympic Champion with the Dutch mixed team.
The women's 4 x 400 metres relay at the 2024 Summer Olympics was held in two rounds at the Stade de France in Paris, France, on 9 and 10 August 2024. This was the 14th time that the women's 4 x 400 metres relay was contested at the Summer Olympics. Sixteen teams were able to qualify for the event through the 2024 World Athletics Relays or the World Athletics top list.
Ireland 
