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][2] Under Brehon Law, Irish men were allowed more than one wife. King Dermot's second wife was Sadhbh Ní Fhaolain.
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.
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.