The men's 100m breaststroke SB8 event at the 2012 Summer Paralympics took place at the London Aquatics Centre on 1 September.

There were three heats; the swimmers with the eight fastest times advanced to the final.

Q = qualified for final.

OC = Oceania Record.

Official London 2012 Paralympics Results: Heats Archived 2012-09-10 at the Wayback Machine Official London 2012 Paralympics Results: Final Archived 2012-09-13 at the Wayback Machine