The women's 100 metre breaststroke competition of the swimming events at the 2015 Pan American Games took place on July 17 at the CIBC Pan Am/Parapan Am Aquatics Centre and Field House in Toronto, Canada.

[1] The defending Pan American Games champion was Ann Catherine Chandler of the United States.

Each National Olympic Committee (NOC) was able to enter up to two entrants providing they had met the A standard (1:11.89) in the qualifying period (January 1, 2014 to May 1, 2015).

NOCs were also permitted to enter one athlete providing they had met the B standard (1:16.20) in the same qualifying period.

[2] All other competing athletes were entered as universality spots.