Mercy Mwethya Joseph (born 21 March 1992) is a Kenyan badminton player. She was selected among the 14 best African players to be a member of the Road to Rio Program organised by the BWF and Badminton Confederation of Africa, to provide financial and technical support to African players and the lead-up to the 2016 Olympic Games in Rio de Janeiro. She was the women's doubles bronze medallist at the 2015 All-Africa Games, and has competed at the 2010, 2014, and 2018 Commonwealth Games.