O'Neill
surname · Latin script
Meaning: from Irish Gaelic, descendant of Niair, a personal name probably meaning literally ‘champion’
Recorded for both men and women· direction only, no split published
/oʊnil/(machine-generated) pronunciation, model-generated
O'Neill is a surname written in the Latin script, with more bearers in the United States than in any other country. In Ireland it is the 17th most common surname.
- IEIreland≈1 in 1.9K(inferred from the name graph)
- AUAustralia≈1 in 3.4K
- GBUnited Kingdom≈1 in 4.3K
carrying the name, as counted by its national register where one exists and as Mondonomo estimates it elsewhere (marked ≈ and "est." on hover). One hue, darker where it is more common; hover a country for its figure.
- United States (measured from records)
- 2 (measured from records)
- Sources
- 404 (measured from records)
- ≈1 in 1.9K (inferred from the name graph)
50,028 people, 2010
recorded for this name
Highest-authority source
Ireland, est.
measured from records inferred from the name graph
Spellings & scripts(measured from records)
One other spelling is counted as the same name:
Locally spelled Oneill in US United States, GB United Kingdom, CA Canada and 1 more.
Spellings marked ● are how people bearing the name write it in our records, and ○ marks a model's transliteration; click a spelling to open its page.
Meaning & origin(measured from records)
from Irish Gaelic, descendant of Niair, a personal name probably meaning literally ‘champion’
Sources 1
- Encyclopedia of surnames [the complete companion to tracing your names history]
Attested in 1 language in the etymology graph.
Where in the world(measured from records)
O'Neill counted together with the spellings and other-language forms grouped with it. Where a register counted another spelling, the row names it.
Sorted by bearers: national registers' counts, and Mondonomo's estimates (≈, est.) where no register counts.
| Country | Most common spelling | Sources | ||||
|---|---|---|---|---|---|---|
| US United States | #497 | 50,028 | 1 in 6.6K | 50K | Oneill | 404 |
| GB United Kingdom | #193 | ≈15,000 est. | ≈1 in 4.3K | 31K | Oneill | 225 |
| AU Australia | #180 | ≈7,600 est. | ≈1 in 3.4K | — | O'Neill | 164 |
| EG Egypt | — | ≈6,800 est. | ≈1 in 15K | — | Oneill | 6 |
| CA Canada | #340 | ≈5,200 est. | ≈1 in 7.3K | — | Oneill | 169 |
| IE Ireland | #17 | ≈2,800 est. | ≈1 in 1.9K | — | O'Neill | 121 |
| NZ New Zealand | #216 | ≈880 est. | ≈1 in 5.6K | — | O'Neill | 103 |
50,028 people counted by Census Bureau — Surname Frequency 2010, 2010. Exact figures are national registers' own counts, while figures marked ≈ and est. are Mondonomo’s estimates, counted from our sources and calibrated against those registers; hover one for how far to trust it in that country. A dash means neither exists.
Registers cited: Census Bureau — Surname Frequency 2010; Surnames of England and Wales (taliesin-arlein.net, Sept 2002 electoral register). Figures without a register are Mondonomo estimates; see Methodology.
Country figures for a list of names, at full precision, are available under licence rather than by scraping this table (how that works).
Other recorded senses(measured from records)
O'Neill is also recorded in 2 other lexicons, as a different name or as an ordinary word. These are senses of the spelling, not of the name above.
In English, Niall 'champion'; great Ulster family, especially Tyrone and Clanaboy branches
as a nameIrish family names
In English, Eugene, US playwright (Nobel
as a namePronouncing Dictionary of Proper Names
Ordered by how much of this spelling's record each language holds, so a sense from a language the name is barely used in sits last rather than first.
Notable people with this name(measured from records)
- Eugene O'Neillb. 1888USnot in their usual nameAmerican playwright (1888–1953)
- Henry O'Neillb. 1891USnot in their usual nameAmerican film actor (1891–1961)
- Oona O'Neillb. 1925GBnot in their usual nameAmerican-British actress (1925–1991)
- Ed O'Neillb. 1946USnot in their usual nameAmerican actor (born 1946)
- Jennifer O'Neillb. 1948BRnot in their usual nameAmerican actress and model
- Michael O'Neillb. 1951USnot in their usual nameAmerican actor
- Martin O'Neillb. 1952GBnot in their usual nameNorthern Irish association football player and manager (born 1952)
- Peter O'Neillb. 1965PGnot in their usual namePrime Minister of Papua New Guinea from 2011 to 2019
- Christopher O'Neillb. 1974GBnot in their usual nameBritish-American businessperson, husband of Swedish Princess Madeleine (born 1974)
- Michelle O'Neillb. 1977IEnot in their usual nameFirst Minister of Northern Ireland since 2024
The ten people covered by the most Wikipedia language editions — a proxy for cross-cultural notability, which favours historical and Western figures over equally prominent contemporary ones — shown by birth year. Source: Wikidata (CC0).
How to address them(machine-generated)
Evidence(measured from records)
Attested in 23 sources across 19 countries.
| Country | Register | Year | Count | Rank |
|---|---|---|---|---|
| GB United Kingdom | Surnames of England and Wales (taliesin-arlein.net, Sept 2002 electoral register) | 2002 | 31K | #214 |
| US United States | wru Name Dictionary — US surnames, voter-file supplement (Khanna et al.) | — | — | — |
Reference works 3
- Nederlandse FamilienamenBank (Dutch surname bank; ex-Meertens Instituut, now CBG)2007
- Wikipedia surname tokens
- Wikidata name items (native-script + romanized given/family names)
These works list the name; their figures are licensed and are not reproduced here.
Register rows as of the 2026-10-09 data build.
Frequently asked questions
- What does the name O'Neill mean, and where does it come from?
- from Irish Gaelic, descendant of Niair, a personal name probably meaning literally ‘champion’ Recorded by Encyclopedia of surnames [the complete companion to tracing your names history].
- In which country does O'Neill have the most bearers?
- In the United States, the national register counted about 50 thousand people named O'Neill, more than in any other country we hold, where it is most often spelled oneill.
- How do you pronounce O'Neill?
- A machine transcription gives /oʊnil/ (IPA) for English.
- How common is the name O'Neill?
- In the United States, the national register counted 50,028 people named O'Neill in 2010, about 1 in 6.6 thousand residents.
- How common is O'Neill compared with other names?
- In the United States, O'Neill is the 497th most common surname of 6,282,806 surnames recorded there.
What do you want to know about O'Neill?
Nobody replies to these one by one, but what readers ask decides what these pages answer next.
Query this name via API
curl -H "X-API-Key: YOUR_KEY" https://api.mondonomo.ai/api/v1/name-graph/o'neillThe payload this page is built from: spellings and scripts, countries and languages, related names, and the registers that attest the form. It takes a free API key (1,000 requests a day), which returns what this page shows everyone; the full country table, every register citation and the year-by-year series come with a licensed key, as does bulk access.
About this data
measured from records inferred from the name graph machine-generated
These figures come from the data snapshot of and will change as it is rebuilt.
Statistics are aggregated from the Mondonomo name corpus; related names and etymology are inferred from the name graph; pronunciation and any machine-marked transliterations are model-generated. Read how the numbers are made, including their known failure modes, and where the data comes from.
Reference works we consult — surname dictionaries, official name registers, Wikidata and Wiktionary — are named directly, beside the claims they support. The per-country source counts also include datasets of person records: we publish how many there are and their authority tier, but not their names.
Cite this page Mondonomo, “O'Neill” — the 497th most common surname in United States. Data snapshot 2026-10-10.