The Men's 100 metre breaststroke competition at the 2017 World Championships was held on 23 and 24 July 2017.

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

The following new records were set during this competition.

[3] The semifinals were held on 23 July at 18:21.

[4] The final was held on 24 July at 17:32.