Mary O'Brien may refer to:
- Mary Ann O'Brien (born 1960), Irish politician
- Dusty Springfield (Mary Isobel Catherine Bernadette O'Brien, 1939–1999), British pop singer
- Mary K. O'Brien (born 1965), American politician and judge
- Mary O'Brien, 3rd Countess of Orkney (1721–1791), mute Irish countess
- Mary O'Brien, 4th Countess of Orkney (1755–1831), Scottish peeress
- Mary O'Brien (philosopher) (1926–1998), feminist political philosopher
- Mary O'Brien (writer) (fl. 1785–1790), Irish poet and playwright
- Mary Grace O'Brien (born 1958), judge of the Virginia Court of Appeals
- Mary F. O'Brien, United States Air Force general
- Mary O'Brien Harris (1865–1938), British politician
This disambiguation page lists articles about people with the same name.
If an internal link led you here, you may wish to change the link to point directly to the intended article.
If an internal link led you here, you may wish to change the link to point directly to the intended article.