Petrus Ua Mórda (Anglicised: Peter O'Mordha, (O')More, or (O')Moore) was Bishop of Clonfert from circa 1150 to 1171.
He appears to have been a member of a family from Ui Maine, one of the oldest and largest kingdoms located in Connacht, Ireland.
Ua Mórda was abbot of Grellach dá Iach, the first of three sites inhabited by the Cistercians, and who finally settled at Boyle Abbey.
He drowned in the River Shannon (Irish: Abha na Sionainne), near Port-da-Chaineg, on 27 December 1171.
The surname is nowadays rendered as Ó Mórdha and Moore.