Dúnlaing (d. 1014), son of Tuathal and overking of Leinster, belonged to the dynasty of Uí Muiredaig. Tuathal (qv) having died as overking (958), Dúnlaing and his brother Augaire strove to maintain the status of their dynasty in the face of aggression from Osraige. In 974 their forces defeated the men of Osraige in the western plain of Liphe (Co. Kildare). Dúnlaing succeeded to the kingship of Uí Muiredaig in 978 when Augaire was slain by the Dublin Norsemen at the battle of Bithlann (probably Belan, Co. Kildare).
Apparently Dúnlaing pursued a policy of rapprochement with neighbouring Osraige. For a time he was married to Aífe, a sister of the Osraige king Donnchad (qv) son of Gilla-Pátraic; she was the mother of his son Echdonn and his daughter Aíbend. Subsequently she married the Uí Chennselaig dynast Donnchad Máel na mBó (qv) and was the mother of his sons Diarmait (qv) and Domnall Remur (qv). Dúnlaing had by other wives at least nine other sons – Donn-cuan, Gilla-Cóemgin, Augaire (qv), Muirchertach, Domnall, Tuathal, Dúnchad, Murchad (qv), and Cú Meda – and three daughters, Ailbe, Cacht (who was also married to an Osraige dynast), and Máel-corcra, who (according to the Life of Welsh king Gruffyd ap Cynan) later married a dynast of the Dublin Norse.
Dúnlaing continued the expansion of his dynasty's lordship eastwards into Co. Wicklow and achieved domination over Glendalough. The naming of his son Gilla-Cóemgin (slain 1019) is significant in this regard. According to the Leinster king-list, Dúnlaing enjoyed overkingship of the province for one month after the death of Uí Fháeláin claimant Máel-mórda (qv) (d. 1014) at Clontarf. He died in penitence at Glendalough early in the summer of 1014. His immediate successor was his son Donn-cuan, who was slain two years later by the rulers of Osraige.