The first few women with a physics Ph.D. from Leiden University
Women entered Leiden University relatively late: The first students arrived in 1878 and the first Ph.D. degree is from 1903 (a thesis in law, by Adolphine Kok). The first four women with a physics Ph.D. all studied theoretical physics, and all four had Hendrik Lorentz as their promotor. This remarkable alignment might be explained by the circumstance that Lorentz's wife, Aletta Lorentz-Kaiser, was deeply involved in the women's rights movement in Leiden.
1912

Johanna Reudler (1880-1962)
promotor Hendrik Lorentz
Over de zwarte straling in ruimten van verschillenden vorm

1912

Geertruida Lorentz (1885-1973)
promotor Hendrik Lorentz
Over de theorie van de Brown'sche beweging en daarmede verwante verschijnselen

1918

Eva Bruins (1885-?)
promotor Hendrik Lorentz
Vraagstukken uit de theorie van het magnetisme

1919

Hendrika van Leeuwen (1887-1974)
promotor Hendrik Lorentz
Vraagstukken uit de electronentheorie van het magnetisme

1938

Anna Keesom (1909-1985)
promotor Willem Keesom
Enkele thermische eigenschappen van vloeibaar en vast helium

1938

Johanna Brunings (1912-?)
promotor Hendrik Kramers
Perturbations in the Ca I spectrum

1940

Henriëtte van der Horst (1883-1948)
promotor Willem Keesom
Metingen met den heliumthermometer: fundamenteele spanningscoefficient, kookpunt van zuurstof