| Brian O'Neill | |
|---|---|
| High King of Ireland | |
| Reign | 1258–1260 |
| Predecessor | Rory O'Connor (1166–1198) |
| Successor | none (Edward Bruce claimant 1315–1318) |
| King of Tyrone | |
| Reign | 1238–1260 |
| Predecessor | Donnell Og O'Neill |
| Successor | Hugh Boy O'Neill |
| Died | 14 May 1260 near Downpatrick, Ireland |
| Issue | Donnell O'Neill |
| Dynasty | Northern Uí Néill (Cenél nEógain) |
| Father | Niall Roe O'Neill |
Brian O'Neill, also known as Brian "of the battle of Down" O'Neill (Irish: Brian Chatha an Dúna Ó Néill), was the High King of Ireland from 1258 to 1260.