| Pronunciation | oh-neel |
|---|---|
| Language(s) | Irish |
| Origin | |
| Meaning | Descendant of Niall |
| Region of origin | Ulster, Ireland |
| Other names | |
| Related names | O'Neil, O'Niall, O'Neall, O'Neal, Neill |
O'Neill is an Irish surname derived from the Gaelic Ó Néill meaning "descendant of Niall". The Uí Néill dynasty were the foremost dynasty of Ulster, and all Ireland,[1] from the 5th century throughout the medieval period, until the Flight of the Earls in 1607 which saw the end of Gaelic Ireland. O'Neill is one of the most common Irish surnames.