The men's 100 metres at the 2015 World Championships in Athletics was held at the Beijing National Stadium on 22 and 23 August.

Justin Gatlin had the world leading time in 2015.

Reigning champion Usain Bolt ran times of 9.96 s in both rounds.

In the final, Bolt finished one hundredth of a second ahead of Gatlin in a time of 9.79 s.[3] There was a tie for third place, with Andre De Grasse and Trayvon Bromell both finishing in 9.911 s, and two bronze medals were awarded.

[4] At 39 years, 139 days old, Kim Collins became the oldest ever competitor for the men's 100 m.[5] Prior to the competition, the records were as follows:[6] All times are local times (UTC+8) Qualification: Best 3 (Q) and next 3 fastest (q) qualify for the next round.