Swimming at the 2016 Summer Olympics – Women's 100 metre breaststroke

The women's 100 metre breaststroke event at the 2016 Summer Olympics took place on 7–8 August at the Olympic Aquatics Stadium.

U.S. swimmer Lilly King stormed home on the final lap in a grudge match against Russia's Yuliya Yefimova to capture the sprint breaststroke title for the first time, since Megan Quann topped the podium in 2000. With 15 metres to go, King launched a mighty surge to pass Yefimova by more than half a second for the gold medal with a time of 1:04.93. King's time also shaved 0.24 seconds off the Olympic record set by Australia's four-time Olympian Leisel Jones from Beijing in 2008. After a successful appeal against doping suspension that allowed her to compete in Rio, Yefimova entered the pool with loud boos from the crowd, but did not let it shake her performance, finishing with a silver in 1:05.50. King's teammate Katie Meili snared the final podium spot with a 1:05.69 for the bronze.

China's Shi Jinglin delivered a time of 1:06.37 to pick up the fourth spot, just ahead of Canada's Rachel Nicol (1:06.68) by about three tenths of a second. Iceland's Hrafnhildur Lúthersdóttir placed sixth in 1:07.18, while Lithuania's world-record holder Rūta Meilutytė could not reproduce her effort from London 2012 with a seventh-place time in 1:07.32. Jamaica's Alia Atkinson, fourth-place finalist at the previous Games, rounded out the top eight with a 1:08.10.

The medals for the competition were presented by Richard Peterkin, IOC member from St. Lucia, and the gifts were presented by Donald Rukare, FINA bureau member.