The men's 100m freestyle S9 event at the 2012 Summer Paralympics took place at the London Aquatics Centre on 7 September.

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

Competed at 17:30.

Q = qualified for final.

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