Yuliya Andreyevna Yefimova (, also romanized Efimova; born 3 April 1992) is a Russian competitive swimmer. After making her Olympic debut in 2008, she went on to win the bronze medal in the 200 metres breaststroke in 2012, and silver medals in the 100 metres and 200 metres breaststroke in 2016. She is a six-time World Champion, winning the 50 metres breaststroke (2009 and 2013), the 100 metres breaststroke (2015), and the 200 metres breaststroke (2013, 2017 and 2019). She is also a former world record holder in the 50 metres breaststroke.