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Surname O'Brien - Meaning and Origin

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O'Brien: What does the surname O'Brien mean?

The last name O'Brien is an old Irish surname originating in the Gaelic name Ó Briain, which literally translates to “descendant of Brian.” According to family historians and genealogists, the clans and septs of the O’Briens descended from the ancient King of Thomond, which is a Province located in the western region of Ireland. It is believed that the King of Thomond, King Brian Boru, reigned from 941-1014 and was responsible for uniting the clans through a series of successful military campaigns.

The surname is part of the larger family of patronage surnames belonging to the Uí Briain, also known as the O’Brien family. Stemming from the eleventh century, the Uí Briain is considered the second most powerful dynasty in medieval Ireland. The O’Briens are part of a network of clans and septs that maintained their own territories and allegiance to the greater Uí Briain, thus making the O’Briens a powerful noble family.

Today, the O’Briens are members of several Irish clans ranging from County Cork, County Limerick, County Tipperary, and County Clare. The O’Briens are one of the few Irish families that still bear the title of ‘The O’Briens’, making them members of the Great Irish Houses. The O’Briens are also famous for their contributions to literature, music, and Irish culture, as the last name is often associated with famous personalities such as Michael Flatley, Julius O’Brien, and Conan O’Brien.

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O'Brien: Where does the name O'Brien come from?

The last name O'Brien is very common in Ireland and other parts of the world. It is one of the most common surnames in Ireland, with an estimated 80,000 people carrying the name. The name originates from the Irish patronymic surname Ó Briain, meaning "descendant of Brian."

O'Briens can be found throughout Ireland, especially in the west of the country. There are many prominent families with this name, including the O'Briens of Thomond, one of the strongest and most powerful Irish dynasties in history.

Outside of Ireland, the name O'Brien is also popular in Australia. About 5,000 people bear the name in the country today, and it is the 68th most common surname in the country. Outside of Australia and Ireland, the surname is fairly common in the United States and can be found in Canada, the United Kingdom, and other English-speaking countries. It is also common in Latin America, where it is often found spelled as O'Bryan.

Variations of the surname O'Brien

The surnames O'Brien and O Briain are variants, spellings and related surnames of the same origin. The origin of the surname is Irish, and is derived from the Gaelic Ó Briain or Ua Briain. It is composed of two Gaelic words. The first is ‘O’ which translates as ‘grandson of’. The second is from the Gaelic ‘Briain’ which is the personal name of an ancestor. Meaning ‘strong’, this name was found in royal Irish dynasties prior to the Norman invasion of 1169.

Variations of the surname O’Brien include Ó Briain, O’Bryan and O’Brien. Ua Briain is the Irish Gaelic spelling of the surname, while Ó Briain is the Irish language spelling and O’Bryan is an anglicised version of the same surname. The related surnames O’Burnian, O’Bryen, O’Bryne, O’Byrne, O’Biran, Brien and Bries are also related to O'Brien, and all derive from the same source.

In some cases, O’Brien is Anglicised as O Briain, but it is often confused with O’Bryan as O Briain is the English version of the Gaelic name. O Briain is also sometimes rendered as O’Brienen.

Many variations of the name have arisen throughout the centuries. In some cases, a sphere of influence caused certain spelling to become dominant. In other cases, literacy and pronunciation issues led to spelling variations. As a result, the direct male line of the O’Briens who were rulers of Thomond as Dál gCais clan are widely dispersed throughout the world today.

Famous people with the name O'Brien

  • Conan O'Brien: Television host and comedian
  • Caitriona Balfe: Actress
  • Liam O'Brien: Voice actor
  • Edna O'Brien: Novelist and playwright
  • Pat O'Brien: Former Major League Baseball sportscaster
  • Michael O'Brien: Former Australian politician and Member of Parliament
  • Malachy O'Brien: Former Australian politician and Member of Parliament
  • John O'Brien: Film director, writer and producer
  • Patrick O'Brian: Novelist
  • David O'Brien: Major League Baseball first baseman
  • Eoin O'Brien: Wrestler and actor
  • Florence O'Brien: Actress and screenwriter
  • Michael O'Brien: U.S. Representative from Ohio
  • Bridget O'Brien: Professional wrestler
  • Bart O'Brien: Scottish civil servant and Lord Lyon
  • Siobhan O'Brien: Irish singer/songwriter
  • Tim O'Brien: Jazz musician
  • Father Seamus O'Brien, S.J.: Jesuit priest
  • Edward O'Brien: United States Navy sailor and Medal of Honor recipient
  • James O'Brien: British radio presenter and political commentator

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