The men's 100 metre breaststroke competition of the swimming event at the 2015 Southeast Asian Games was held on 7 June at the OCBC Aquatic Centre in Kallang, Singapore.
Prior to this competition, the existing Asian and Games records were as follows:
All times are Singapore Standard Time (UTC+08:00)
The heats were held on 7 June.
Heat 1 was held on 7 June.
Heat 2 was held on 7 June.
The final was held on 7 June.