Doo Hoi Kem (Chinese: 杜凱琹; born 27 November 1996) is a Hong Kong table tennis player. She won two medals at the 2014 Summer Youth Olympics and she was a member of Hong Kong women's team at the 2014 World Team Championships. In 2015, she won a bronze medal in mixed doubles event with Wong Chun Ting at the World Championships. In 2021, she also won bronze in the women's team event with Lee Ho Ching and Minnie Soo Wai Yam at the 2020 Summer Olympics.
At the 2016 Summer Olympics, Doo competed in the team event along with Lee Ho Ching and Tie Ya Na. They lost to Germany in the quarterfinals. In the 2020 Summer Olympics, Doo reached the quarter-finals in the women's single event where she lost to top seed Chen Meng after leading 2–0. In one of the more interesting wrinkles of the tournament, play was stopped mid-game in Doo's match against Chen so that Doo could cover a logo on her pants with duct tape (due to Olympic sponsorship rules). Doo, along with her teammates Lee Ho Ching and Minnie Soo Wai Yam, won bronze in the women's team event, defeating Germany with 3–1 in the bronze medal match.