Mary O'Sullivan may refer to: Mary Blanche O'Sullivan (1860–?), Canadian teacher, writer, and editor Mary Josephine Donovan O'Sullivan (1887–1966), Irish professor of history Mary Kenney O'Sullivan (1864–1943), American organizer in the early U.S. labor movement Mary O'Sullivan, Irish camogie player from 1958 and 1959 All-Ireland Senior Camogie Championship Mary Rhys-Jones (née O'Sullivan) (born 1965), British charity worker and secretary, mother of Sophie, Countess of Wessex