Mary O'Sullivan may refer to:
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Mary Kenney O'Sullivan
Mary Kenney O'Sullivan (January 8, 1864 – January 18, 1943), was an organizer in the early U.S. labor movement. She learned early the importance of unions from poor treatment received at her first job in dressmaking. Making a career in bookbind ...
, organizer in the early U.S. labor movement
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Mary Blanche O'Sullivan, Canadian teacher, writer, and editor
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Mary Josephine Donovan O'Sullivan, professor of history
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Mary Rhys-Jones (née O'Sullivan), British charity worker and secretary, mother of Sophie, Countess of Wessex
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Mary O'Sullivan (camogie), Irish camogie-player
{{hndis, Osullivan, Mary