Kylie Jacqueline Masse (born January 18, 1996) is a Canadian competition swimmer who specializes in the backstroke. She tied for the bronze medal at the 2016 Summer Olympics in 100 m backstroke. Masse is the current world champion in the 100 m backstroke, breaking the eight year old world record in the process, which she held until July 2018. While winning her title in Budapest at the 2017 World Aquatics Championships she became the first Canadian woman to become a world champion in a swimming event. She subsequently became the first Canadian woman to defend her world title at the 2019 World Aquatics Championships.
Masse won two gold medals at the 2018 Commonwealth Games in the 100 m and 200 m backstroke, setting a games record in both events, and finished the games with a silver in the 50 m backstroke.
She is also the Canadian record holder in the 100 m back. Masse won gold in the 100 m backstroke at the 2015 Summer Universiade and was the 2015-16 CIS swimmer of the year while swimming at the University of Toronto.