The Men's 100 metre butterfly competition of the 2018 European Aquatics Championships was held on 8 and 9 August 2018.

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

The heats were started on 8 August at 09:35.

[3] The semifinals were started on 8 August at 17:17.

[4] The final was started on 9 August at 17:00.