The Ó Meadhra clan were a sept of the Dal gCais, and the name is most common in the dynasty's homeland of north-east Thomond (nowadays north County Tipperary and adjoining parts of County Clare. The family's home district was centered about Toomevara (O'Meara's tumulus).
The surname is now anglicised as Meara, O'Meara or O'Mara.
- Dermod O'Meara, physician and poet, fl. 1619.
- Edmund O'Meara, physiologist, c. 1614–1681.
- Dermot O'Meara, physician, c. 1614-42.
- Barry Edward O'Meara, surgeon, 1786-1836.
- Kathleen O'Meara, writer, 1839-1888.
- Joseph O'Mara, opera singer,1866-1927.
- Kathleen O'Meara, politician, born 1960.
- Aileen O'Meara, journalist, twin sister of the above.
- Frank O'Meara, Irish artist, c. 1902
- Piers Morgan, born Piers Stefan O'Meara
- Donn O'Meara, author, linguist, 1924-2004
- Barry O'Meara, doctor, Napoleon's physician at St Helena
- Martin O'Meara, Victoria Cross holder from the first World War
- Mark O'Meara, professional golfer
- Ollie O'Mara, professional baseball player
- Anne Meara, actress
- Jared O'Mara (born 1981), British politician
- O'Meara : the descendants of three sons of Ireland, John, Patrick and Michael, who came to New Zealand and settled in Southland and Masterton, John F. Tourelle, Annabelle O'Meara Ltd., Arrowtown, New Zealand, 1998 (National Library of New Zealand P q929.2 OME TOU 1998)
- A historical profile of the O'Meara, O'Mara family: the Dalcassians of Ireland, Irish Families Historical Society, New Jersey, 1993 (Library of Congress CS499 .O62 1993)