Discover your heritage: a history of Irish surnames

As part of our blog series exploring ancestry and heritage, we’ve been exploring common surnames from different parts of the UK, and learning more about the history of these names. Hundreds of years ago, surnames were added on as the population grew to distinguish different people. Now, a surname is a strong tie to our family and blood, and can be traced back generations to build our family trees. 

This week, we’ve put the spotlight on Ireland and will be taking a look at some of the most common surnames in Ireland, and where they originated from.

“Mc” and “O” – Similarly to other UK countries (particularly Wales and Scotland), prior to the 10th Century many Irish surnames originated as patronymic names, which means they came from the name of the father (Mc) or grandfather/notable ancestor (O).

For example:  Brian’s son would be called Connor McBrian (son of Brian). When Connor had a son, his son would be called Sean McConnor (Son of Connor).
If Brian had been a particularly notable or well-known person, it would be very likely that the grandson would have been called Sean O’Brian instead, because this name would have been more recognisable among the other local people. This is how family names worked for a long time in Ireland, and the remnants of this part of history can still be seen very clearly in Ireland.

Speaking of which, here are the top 10 most common surnames in Ireland, with a bit of background.

1. Murphy 

Murphy is the most common Irish surname, with many famous holders, including Peaky Blinders Cillian Murphy! The name is the anglicized version of Ó Murchadha and Mac Murchadha which mean “sea warrior”. 

2. Kelly

Although there are some different origins of the name, from an Irish standpoint Kelly is commonly an anglicised version of the surname Ó Ceallaigh (Son of Ceallaigh). The name Ceallaigh would have originally been a personal name for someone, and translates as “bright-headed”.

3. O’Sullivan 

The exact meaning of O’Sullivan is still up for debate, as the Gaelic word ‘suil’ means eye, but researchers are unsure of the latter part. It could possibly mean “one-eyed, “black-eyed” or “hawk-eyed”. The name, in all its various forms, is most common in Munster and was a notable clan name.

4. Walsh
In the late 1100s many British travelled over to Ireland during the Norman Invasion, and brought with them the surname Walsh – which literally means “from Wales” or “Welsh”, but was often used to refer to anybody from Britain, who were all considered “foreigners”.

5. Smith
Smith takes a place in every top 10 list in the UK, but many consider the Irish version of this name to have its own individual heritage not directly linked with the English version. Many of the Smiths from Ireland were originally from the Gabhann family, which means Smith in Gaelic, but changed their names to the English spelling at the same time all names began to become anglicised. 

6. O’Brien
Another notable Irish clan name, this surname originated from the clan of Brian Boru (941-1014) who was the King of Munster. All of his descendants in the area took the name O’Brien to signify “descendants of Brian”. 

7. Byrne
As with many Irish surnames, there’s a variety of different common spellings for Byrne including Burns and O’Byrne. These all originate from the Irish name Ó Broin, meaning “descendant of Bran”, referring to Bran mac Máelmórda, King of Leinster, in the 1100s.

8. Ryan
First found in Tipperary, it derives from the Gaelic ‘Ó Riagháin’. This means descendant of Rían. Modern day translations of this also suggest that Rian meant ‘little king’, although the exact meaning of this surname is still disputed.
9. O’Connor
Like many of the surnames beginning with O’ – O’Connor simply comes from the traditional Irish for Ó Conchobhair, and means grandson or descendant of Conchobhair (modern day version is Connor). Connor is said to mean “lover of hounds”.

10. O’Neill

Just like the previous name, O’Neill is a simple translation, and means grandson or descendant of Niall. The name Niall itself is linked to meanings such as “champion” and “vehement”. Similar surnames include Neill and Neale. 

We hope our series of surname blogs has helped to uncover some valuable information on your family history and origins. If you want to learn more about how to preserve your family legacy and create lasting documentation of your family tree for the future, take a look at some of our other blogs on the site for more inspiration.  

Clans are an integral part of Scottish history, and throughout the world millions of people of Scottish descent take pride in their clan and common kinship with others bearing the same surname.

Surnames offer us a sense of identity, and learning more about where we come from helps to improve our wellbeing and provides us with a deeper sense of belonging and connection to the world. Take a look at our blog to see if your Scottish surname is on our list of names with clan links!


The earliest record of clans dates back to the 12th century, but the same clan names used all those many years ago are still in common use now as surnames. The term clan is derived from the Gaelic term “clanna” meaning children, although many clans included followers that were not blood related, but had pledged allegiance to the clan leader in order to gain protection and kinsmanship with fellow clansmen. As well as the name being passed down through the family, it was also a territory-based form of identification.

In the 16th and 17th century, surnames were introduced into Scottish culture through anglicisation, and it was in this time period that many Scots chose to bear the name of their clan as their surname. There were over 500 clans across the history of Scotland, but some that have remained popular surnames to this day are below.

The name Campbell derived from the Gaelic roots cam (“crooked”) and beul (“mouth”)—that originated as a nickname meaning “crooked mouth” or “wry mouthed.” Clan Campbell was one of the most notable and powerful clans in Scotland and dominated the Highland areas.

The name Stewart derived loosely from a Gaelic term which means guardian or warden (similar to the term steward which we still use to this day) and were originally of royal descent.

Based in the Scottish borders where the country meets with England, Clan Scott were historically involved in many battles to preserve their territory against the English and were also well known for their rallying cry to battle.


Clan Donald was one of the largest clans in the Highland areas and had a range of different branches including Clan Macdonald of Sleat, Clan Macdonald of Clanranald, Clan MacDonell of Glengarry, Clan MacDonald of Keppoch, and Clan MacAlister.

Clan Murray is another highland clan, descended from the 12th Century Flemish warlord Freskin. Clan Murray has the unique honour of maintaining Europe’s only legal private army. Duffus Castle, their historical stronghold, was once one of Scotland’s strongest castles.

In this post, we’ve highlighted some of the key facts about Scottish history and clans, but there are many more interesting facts and bits of information to be found on the Visit Scotland website.