Marguerite Catherine Perey (October 19, 1909 - May 13, 1975) was a French physicist. In 1939, Perey discovered the element francium by purifying samples of lanthanum that contained actinium. She was a student of Marie Curie. In 1962, she was the first woman to be elected to the French Acad矇mie des Sciences, an honor denied to her mentor Curie. She died of cancer in 1975 at the gas of 65.