Liu Ou (, born 13 November 1986) is a Chinese synchronized swimmer.
Liu competed in the women's team event at the 2008 Summer Olympics where she won a bronze medal. She followed up this success in the women's duet and women's team events at the 2012 Summer Olympics where she won a bronze (with Huang Xuechen) and silver medal respectively.
After her retirement in 2013, Liu Ou went to the United States to coach the Santa Clara Aquamaids.