Mary O'Leary

Mary O'Leary may refer to:


 * Mary O'Leary (producer), American soap opera producer
 * Mary O'Leary (camogie), Irish former camogie player
 * Mary O'Leary (Big Brother), Irish reality show contestant
 * Liz Truss (born 1975), British former Prime Minister, whose birth name was Mary and is married to Hugh O'Leary