Robert Cusack (c.1516–1570) was an Irish judge of the sixteenth century, who held office as a Baron of the Court of Exchequer (Ireland). He was strongly recommended for the position of Chief Baron of the Irish Exchequer, but was passed over for the office, though with a promise of future preferment. His career was cut short by his premature death. He came from a prominent Anglo-Irish landowning family of the Pale. Although his legitimacy was questionable, as his father denied that he had been lawfully married to his mother, this did not harm his career.