The Women's 100 metre butterfly competition at the 2019 World Championships was held on 21 and 22 July 2019.

[1][2] Prior to the competition, the existing world and championship records were as follows.

The heats were held on 21 July at 10:45.

[3] The semifinals were held on 21 July at 20:12.

[5] The final was held on 22 July at 20:10.