Margaret Evelyn Osborne duPont (born on March 4, 1918, in Joseph, Oregon, United States) is a former American female tennis player.
DuPont won a total of 37 singles, women's doubles, and mixed doubles Grand Slam titles, which places her fourth on the all-time list despite never entering the Australian Championships. She won 25 of her Grand Slam titles at the U.S. Championships.
DuPont teamed with Louise Brough Clapp to win 20 Grand Slam women's doubles titles. They won nine consecutive titles at the U.S. Championships from 1942 through 1950. They won that tournament 12 of the 14 years they entered as a team.
DuPont was ranked in the U.S. top 10 (seventh) for the first time in 1938. Her last U.S. top 10 ranking (fifth) was in 1958. Over that 21 year period, she was ranked in the U.S. top 10 fourteen times.
DuPont was undefeated in ten Wightman Cup competitions, winning her ten singles and nine doubles matches. She also captained the U.S. team nine times, winning eight.
DuPont married William duPont in 1947 and later interrupted her career to give birth to a son. She was one of the few women to win a major title after childbirth.
DuPont never played the Australian Championships because her husband would not let her. "They didn't start to invite people down there and pay their expenses until I got married, and that was wintertime and Will's vacation time, and I just never got to go. He threatened to divorce me if I went to Australia, so I never went. He had that respiratory trouble, and he wanted me to come to California with him. He thought I should be with him. That was that."
She was inducted into the International Tennis Hall of Fame in 1967.

Grand Slam singles finals

Wins (6)

Grand Slam singles tournament timeline

Performance timelines for all female tennis players who reached at least one Grand Slam final