Swimming at the 2023 Pan American Games – Men's 100 metre butterfly

The men's 100 metre butterfly competition of the swimming events at the 2023 Pan American Games were held on October 22, 2023, at the Aquatic Center in Santiago, Chile.

Records
Prior to this competition, the existing world and Pan American Games records were as follows:

Heats
The highest eight scores advance to the final.

Final B
The B final was held on October 21.

Final A
The A final was held on October 21.