Billie Jean King (née Moffitt; born November 22, 1943) is an American former professional tennis player. She won 12 Grand Slam singles titles, 16 Grand Slam women's doubles titles, and 11 Grand Slam mixed doubles titles. She is an advocate for sexual equality and won "The Battle of the Sexes" tennis competition in 1973. She completed a career tour all surfaces win-loss performance of 81.76% (696-165). Her win-loss performance in all Grand Slam singles tournaments was 82.00% (190-39), at the French Open 77.77% (21-6), at Wimbledon 86.36% (95-15), at the US Open 80.55% (58-14), and at the Australian Open 80.00% (16-4).
King is the founder of the Women's Tennis Association, the Women's Sports Foundation, and owner of World Team Tennis, which was founded by her former husband, Larry King, Dennis Murphy, Frank Barman, and Jordan Kaiser.