The Men's 100 metre backstroke competition of the swimming events at the 2015 World Aquatics Championships was held on 3 August with the heats and the semifinals and 4 August with the final.

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

The heats were held on 3 August at 09:49.

[2] The semifinals were held on 3 August at 17:48.

[3] The final was held on 4 August at 18:36.