| 6 June 2015|
| 11 from 8 nations|
| OCBC Aquatic Centre, Singapore Sports Hub|
The Men's 100 metre backstroke event at the 2015 Southeast Asian Games took place on 6 June 2015 at the OCBC Aquatic Centre in the Singapore Sports Hub.
There were 11 competitors from eight countries who took part in this event. Two heats were held. The heat in which a swimmer competed did not formally matter for advancement, as the swimmers with the top eight times from both field qualified for the finals.
Swimming at the 2015 Southeast Asian Games – Men's 100 metre backstroke Wikipedia
All times are Singapore Standard Time (UTC+08:00)
Prior to this competition, the existing world, Asian, and Southeast Asian Games records were as follows.
The following records were established during the competition: