The women's 100 metres event at the 2020 Summer Olympics took place on 30 and 31 July 2021 at the Japan National Stadium. [1] 71 athletes from 55 nations competed at the event. [2] The defending champion, Elaine Thompson-Herah, won the event in 10.61 secs, to break Florence Griffith-Joyner 's 33-year-old Olympic record.