Robert FitzStephen (c.1120–1183) is a Cambro-Norman soldier, one of the leaders of the Norman invasion of Ireland, for which he is granted extensive lands in Ireland.
He is a son of the famous Nest, daughter of Rhys ap Tewdwr, the last king of Deheubarth (South Wales).
His father was Nest's second husband, Stephen, Constable of Cardigan (Welsh: Aberteifi).
Following the death of her first husband, Gerald de Windsor, her sons had married her to Stephen, her husband's constable for Cardigan.
By Stephen, she has another son, possibly two; the eldest is Robert, and the younger may have been Hywel.