The 400 metres hurdles is a track and field hurdling event. The event has been on the Olympic athletics programme since 1900 for men and since 1984 for women.

Sydney Michelle McLaughlin-Levrone is an American hurdler and sprinter who competes in the 400 meters hurdles. She is the 2020 Tokyo Olympic champion with the Games record, and 2022 World champion with a world record time of 50.68 seconds. Setting four world records during 13 months, she was the first woman to break the 52-second and 51-second barriers in the 400 m hurdles. She won the silver medal at the 2019 World Championships. At all three competitions, she also took gold as part of a women's 4 × 400 m relay team.