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Irish Names that Start With O

Updated October 2026

Names28

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Total Names28

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About this list

There are 28 Irish names that start with the letter O for boys and girls, including Oscar, Orin, Orla, Ozzy, Oona, Oisin, Oran, Odhran, Orna, O'keeffe, O'brien, O'hara, O'brian, O'callahan, O'connor, O'donnell, O'donovan, O'fallon, O'grady, and O'keefe.

The names

Showing 1–20 of 28

Oscar
English or Irish
"God spear, or deer-lover or champion warrior"
Oscar is one of the most stylish Old Man Names of our era. While it's softened slightly in popularity over the past 20 years, that may be considered a very good thing. In the nineties and the…
Orin
Variation of Oren or Oran, Hebrew, Irish, Scottish
"laurel, light, song, little green one"
Orin is one of a variety of similarly-spelled names that have a soft and sensitive image. The Orrin spelling has been known nationally via Republican Senator Hatch. Orin is the name of a character in…
Orla
Irish
"golden princess"
Orla is an Irish name closely associated with the high king Brian Boru, as it was the name of his sister, daughter and niece. It was very popular in the Middle Ages – the fourth most popular name in…
Ozzy
Short form of Oscar or Osborn, English or Irish
"deer; divine"
This grandpa-esque nickname, traditionally short for masculine names like Osmond, Oscar, or Oswald, is starting to get traction on its own, thanks to its cool, zippy sound. In the Top 1000 for boys…
Oona
Irish, variation of Una
"lamb"
Oona is a name made famous by Eugene O'Neill's daughter, who became Charlie Chaplin's wife. One of the original Oona's granddaughters was named after her, and is now an actress famous in her own…
Oisin
Irish
"little deer"
Oisin is one of the most popular Irish baby names in its native land, though largely unknown in the US. The original Oisin was the mythological son of Finn McCool and Sadb, the goddess who was…
Oran
Hebrew, Irish, Scottish
"light, song, little green one"
A calm and gentle multicultural choice. Oran is popular in Ireland, where its Gaelic form is Odhrán, meaning "little green one". In Scottish Gaelic, the name means "song", and in Hebrew, it's a…
Odhran
Irish
"little pale green one"
Odhran, Anglicized as Oran, was the name of an ancient saint. Today, Odhran is among the Top 100 Irish names for boys in Ireland.
Orna
Irish
"little pale green one"
This Irish saint's name sounds like a lopped-off Lorna.
O'keeffe
Irish surname
If you love the venerable Southwestern painter but feel Georgia's gotten too overheated, you might want to go all the way to this Irish surname in the fashionable O' family.
O'brien
Irish
"descendant of Brian"
The use of O -prefixes could create the next wave of Irish-inflected names, offering an innovative way of honoring a relative with the old-fashioned moniker Brian. On Downton Abbey , the surname…
O'hara
Irish
"son of Eaghra"
The O'Haras are descended from Eaghra -- pronounced and phonetically spelled Ara -- the lord of Luighne, the modern Leyney in County Sligo. As a name, this makes a satisfying new twist on Harry, and…
O'brian
Irish
"descendant of Brian"
Irish surname that refers to High King Brian Boru, also spelled O'Brien. Makes a fabulous first name.
O'callahan
Irish
"son of the church lover"
One of the most usable of the fashionable O'Names.
O'connor
Irish
"son of the hound lover"
Perfect name for the child of dog enthusiasts, and much more distinctive than the trendy Connor.
O'donnell
irish
"son of the brave one"
Forget Donald. Honor Grandpa Don with this new spin.
O'donovan
Irish, 'son of the dark one"
Donovan is on the rise, so why not this sequel?
O'fallon
Irish
"son of the leader"
Fallon has gone feminine, but this puts it back in the boys' camp.
O'grady
Irish
"son of the noble one"
Like the other O' names, this is a wonderful way to pass down a family name.
O'keefe
Irish
"son of the kind one"
Most parents interested in this name would be honoring either an ancestor or painter Georgia O'Keeffe.

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