The men's 100 metre breaststroke event at the 2024 Summer Olympics was held from 27 to 28 July 2024 at Paris La Défense Arena, which was converted to a swimming pool for the swimming events.

Prior to this competition, the existing world and Olympic records were as follows: Each National Olympic Committee (NOC) was permitted to enter a maximum of two qualified athletes in each individual event, but only if both of them had attained the Olympic Qualifying Time (OQT).

World Aquatics then considered athletes qualifying through universality; NOCs were given one event entry for each gender, which could be used by any athlete regardless of qualification time, providing the spaces had not already been taken by athletes from that nation who had achieved the OQT.

[5][6] Finally, the rest of the spaces were filled by athletes who had met the Olympic Consideration Time (OCT), which was 59.79 for this event.

[5] In total, 21 athletes qualified through achieving the OQT, 15 athletes qualified through universality places and two athletes qualified through achieving the OCT.[6] All times are Central European Summer Time (UTC+2) The swimmers with the best 8 times, regardless of heat, advanced to the final.