Swimming at the 1988 Summer Olympics – Men's 100 metre breaststroke

The men's 100 metre breaststroke event at the 1988 Summer Olympics took place between 18–19 September at the Jamsil Indoor Swimming Pool in Seoul, South Korea.

The winning margin was 0.01 seconds which as of 2023 remains the only time this event for men has been won at the Olympics by less than a tenth of a second.

Records
Prior to this competition, the existing world and Olympic records were as follows.

Heats
Rule: The eight fastest swimmers advance to final A (Q), while the next eight to final B (q).

Swimoff
* Opted to swim for the consolation final instead.