Mary Gwynne Jestyn Jeffreys, Mrs Emery (8 January 1908 – 19 June 1973) was a Welsh amateur golfer.

[1][2] in 1930 she beat the defending champion, Alison Rieben, by two holes in the 36-hole final.

[5] Her fourth win came in 1937, beating Philomena Whitaker in the final, 10&9, having been 6 up after the morning round.

[6] Jeffreys represented Wales in the Women's Home Internationals each year from 1928 to 1938 and again in 1947.

[2] In 1934, she became the first Welsh woman to play in a British team when she competed in the Vagliano Trophy match against France at Chantilly.