The women's flyweight boxing event at the 2020 Summer Olympics took place between 25 July and 7 August 2021 at the Ryōgoku Kokugikan.

The 2016 Olympic champion, Nicola Adams of Great Britain, turned professional and did not attempt to qualify.

A National Olympic Committee (NOC) could enter only 1 qualified boxer in the weight class.

The competition begins with a preliminary round, where the number of competitors is reduced to 16, and concludes with a final.

Judges consider "number of blows landed on the target areas, domination of the bout, technique and tactical superiority and competitiveness."