Domnall Ua Briain and Domhnall Ua Briain may refer to:
Domnall Gerrlámhach (died 1135), King of Dublin Domnall mac Taidc (died 1115), King of the Isles, King of Thomond Domnall Mór Ua Briain (died 1194), King of Thomond
See also Donal O'Brien (disambiguation)