Tadhg Cael Uisce Ó Briain

Tadhg Cael Uisce Ó Briain (c. 1230–1259) was the eldest son of Conor na Siudane Ua Briain and tánaiste, or heir-designate, of Thomond. He took his byname from the conference of Cael Uisce, where as his father's representative he refused to acknowledge Brian Ua Néill as High King of Ireland.

He died in 1259 before his father, leaving a young son, Toirdhealbhach Mór, whose descendants led the Clann Tadhg claim to Thomond.