Mary King (born 8 June 1961) is a British horse rider. She won the European Championships and the Badminton Horse Trials. She won four gold medals at the World and European championships. She was the British Champion a record four times. Her sixth Olympic appearance was in London at the 2012 Summer Olympics.
King and her daughter Emily were the first British mother and daughter team to represent Britain in their respective age groups, Mary at senior and Emily (15 years old) at junior level.