Owen Keir Davidson (born 4 October 1943) is a former professional tennis player of the 1960s and 1970s. Partnering Billie Jean King, Davidson won eight grand slam mixed doubles titles. In 1967 he won a calendar year slam for mixed doubles, when he won the Australian Championships (with Lesley Turner Bowrey), and the French Championships, Wimbledon and the US Championships (with King). Davidson became the first player to win a match in the open era of tennis when he defeated John Clifton in the first round of the British Hard Court Championships in Bournemouth played in April 1968.