Skip to main content - O'Day, Caroline (1869–1943)
- O'Doherty, Mary Anne (1826–1910)
- O'Donnell, Mary Stuart (fl. early 1600s)
- O'Donnell, Phyllis (1937—)
- O'Hagan, Mary (1823–1876)
- O'Hair, Madalyn Murray (1919–1995)
- O'Hara, Mary (1885–1980)
- O'Hara, Maureen (1920—)
- O'Hare, Kate Richards (1876–1948)
- O'Keeffe, Adelaide (1776–c. 1855)
- O'Keeffe, Georgia (1887–1986)
- O'Kelley, Mattie Lou (c. 1908—1997)
- O'Malley, Grace (c. 1530–1603)
- O'Neil, Kitty (1947—)
- O'Neill, Carlotta (1888–1970)
- O'Neill, Eliza (1791–1872)
- O'Neill, Maire (1885–1952)
- O'Neill, Rose Cecil (1874–1944)
- O'Reilly, Leonora (1870–1927)
- O'Shea, Katherine (1845–1921)
