Muiredach mac Ainbcellaig was king of the Cenél Loairn and of Dál Riata (modern western Scotland) from about 733 until 736.
His coming to power is reported in 733, and is not obviously associated with the death of Eochaid mac Echdach, the contemporary king of Dál Riata, in the Irish annals.
It is not certain who preceded Muiredach as king of the Cenél Loairn, but it may have been his cousin Dúngal mac Selbaig.
It is likely that his reign ended as a result of his defeat at the hands of the Picts of Fortriu, led by Talorgan mac Fergusa, brother of Óengus, at "Cnoc Cairpri in Calathros at Etarlinde".
The next king of Dál Riata reported by the Irish annals is Áed Find, of the Cenél nGabráin, named in 768.