| Consort: | yes |
| Mór Ní Thuathail | |
| Succession: | Queen consort of Leinster |
| Reign: | c. 1140 – 1 May 1171 |
| Spouse: | Diarmait Mac Murchada, King of Leinster |
| Issue: | Conchobhar MacMurrough Aoife of Leinster Orlachan of Leinster |
| House: | O'Toole Mac Murchada |
| Father: | Muitchertach Ua Tuathail |
| Mother: | Cacht Ní Morda |
| Birth Date: | c. 1114 |
| Birth Place: | Castledermot, County Kildare, Ireland |
| Death Date: | 1191 |
| Death Place: | Ireland |
Mór Ní Thuathail (anglicised as Mor O'Toole) (c. 1114–1191) was a Queen-consort of Leinster as the principal first wife of King Diarmait Mac Murchada.[1] Under Brehon Law, Irish men were allowed more than one wife. King Dermot's second wife was Sadhbh Ní Fhaolain.
Mór was the mother of Aoife of Leinster, the wife of Richard de Clare, Earl of Pembroke, known to history as Strongbow.[2]
Mór was born in Castledermot, Kildare, Ireland in about 1114, the daughter of Muirchertach Ua Tuathail, King of the Uí Muiredaigh, and Cacht Ní Morda.
Her paternal grandparents were Gilla Comgaill Ua Toole and Sadbh Ní Domnail and her maternal grandparents were Loigsig Ua Morda, King of Laois and Gormlaith Ní Caellaide.
One of Mór’s four half-brothers was St. Lorcán Ua Tuathail, Archbishop of Dublin, who was canonised in 1225 by Pope Honorius III.
Sometime about 1140 in Loch Garman, County Wexford, Mór was married to King Diarmait Mac Murchada of Leinster as his principal first wife, making her Queen-consort of Leinster. His second wife was Sadhbh Ní Fhaolain. Under Brehon Law, Irish men were permitted more than one wife. In 1152, he abducted Derbforgaill Ní Mhaol Seachlainn, the wife of the King of Breifne, Tighearnán Ua Ruairc (Irish: Tighearnán Ua Ruairc).
Together Dermot and Mór had about three children:
In 1167, Mór's son Conchobhar was killed by Ruaidrí Ua Conchobair, High King of Ireland, after having been taken hostage while Diarmait waged war against Ruaidrí with the aim of overthrowing him in order to take his place as the High King.
Queen Mór died in 1191, three years after her eldest daughter, Aoife. Her husband predeceased her on 1 May 1171 in Ferns, shortly after the Cambro-Norman invasion of Ireland led by their son-in-law, Strongbow.