The Men's 100 metre butterfly S8 event at the 2016 Paralympic Games took place on 9 September 2016, at the Olympic Aquatics Stadium.

Two heats were held.

The swimmers with the eight fastest times advanced to the final.

11:19 9 September 2016:[1] 11:23 9 September 2016:[1] 20:15 9 September 2016:[2]