Everything you need to know about the Irish surname O'Brien - its meaning, origins, interesting facts, and famous people with the last name O'Brien.

Irish derivation of O'Brien:

Ó Briain.

Name meaning of O'Brien:

 "Descendant of Brian (Boru)."

Counties associated with the name O'Brien:

Cork, Clare, Donegal, Dublin, Fermanagh, Kilkenny, Limerick, Meath, Tipperary, Wexford, and Wicklow.

O'Brien Coat of Arms motto:

"The strong hand from above."

O'Brien history:

Ó Briain, a Dalcassian sept, derives its name and importance from the family of King Brian Boru. O'Brien is now a very popular name in all provinces of Ireland including Munster.

The family clans of the O’Brians have great importance in Ireland. This is mainly due to their illustrious predecessor, the great Brian Born, King of Leinster and Munster, who fought the Vikings at the Battle of Clontarf.

The surname O’Brian comes from the Irish name, as Gaeilge, O’Briain, which means "son of Brian". Brian is an ancient Celtic name of uncertain origin-but the most likely explanation is that it means "hill".

Interesting facts about the Irish family name:

  • Queen Elizabeth II's maternal eighth great grand-mother was an O'Brien. 
  • Emerged as chiefs of the Dalcassian races from the southwest of Ireland. 
  • Founded by Brian Boru.

Some famous O'Briens:

  • Conan O'Brien (b.1963, US comedian and talk show host)
  • Soledad O'Brien (b.1966, journalist)
  • Mick O'Brien (b.1961, traditional Irish musician)
  • Miles O'Brien (b.1959, journalist and CNN anchor)
  • Richard O'Brien (b.1942, actor and writer of cult hit 'Rocky Horror Picture Show')

Here's a short documentary on the Irish name, O'Brien:

Looking for more on your Irish surname? Visit our Irish clans and surnames page here

* Originally published in 2016. Updated in 2022.