The women's 100 metres at the 2021 World Athletics U20 Championships was held at the Moi International Sports Centre, Kasarani Stadium on 18 and 19 August.

Records

Results

Heats

Qualification: First 4 of each heat (Q) and the 4 fastest times (q) qualified for the semifinal. Wind:
Heat 1: +0.5 m/s, Heat 2: +0.5 m/s, Heat 3: +1.0 m/s, Heat 4: -0.1 m/s, Heat 5: -0.9 m/s

Semifinals

Qualification: First 2 of each heat (Q) and the 2 fastest times (q) qualified for the final. Wind:
Heat 1: 0.0 m/s, Heat 2: +0.3 m/s, Heat 3: -0.5 m/s

Final

The final was held on 19 August at 18:10. Wind: -0.6 m/s

References

{{DEFAULTSORT:2021 World Junior Championships In Athletics - Women's 100 metres 2021 World Athletics U20 Championships, 100 metres 100 metres at the World Athletics U20 Championships 2021 in women's athletics, U20