The Men's 100 metre breaststroke competition of the swimming events at the 2015 World Aquatics Championships was held on 2 August with the heats and the semifinals and 3 August with the final.

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

The following new records were set during this competition.

[2] The semifinals were held on 2 August at 18:35.

[3] The final was held on 3 August at 17:32.