 |
| Muirchertach Ua Briain | |
|---|---|
| King of Munster and High King of Ireland | |
 Fanciful depiction | |
| Reign | c.1075-1086 |
| Predecessor | Toirdelbach Ua Briain |
| Successor | Tairrdelbach Ua Conchobair |
| Born | c. 1050 |
| Died | 1119 |
| Issue | Mathgamain Domnall Bjaðmunjo Lafracoth |
| House | Uí Briain |
| Father | Toirdelbach Ua Briain |
| Mother | Derbforgaill, daughter of Tadhg Mac Giolla Pádraig of Osraige |
Muircheartach Ua Briain (anglicised as Murtaugh O'Brien; c. 1050 – c. 10 March 1119), son of Toirdelbach Ua Briain and great-grandson of Brian Boru, was King of Munster and later self-declared High King of Ireland.