Swimming at the 2017 World Aquatics Championships – Men's 100 metre butterfly

The Men's 100 metre butterfly competition at the 2017 World Championships was held on 28 and 29 July 2017.

Records
Prior to the competition, the existing world and championship records were as follows.

Heats
The heats were held on 28 July at 10:10.

Semifinals
The semifinals were held on 28 July at 18:35.

Final
The final was held on 29 July at 18:13.