The author examines the place of consent in treaty interpretation at the time of the marginalization of the role of the intention of the parties. Whether the characterization of international law as a legal system grounded in State consent has ever been empirically true is, as he argues, open to discussion. For him, the law of treaties, however, is commonly seen as ‘a bastion of consensualism’. This sense of confidence has, however, never sat easily with treaty interpretation. The author claims that, despite the lip service sometimes paid to the fiction of the common intention of the parties, the official doctrine of treaty interpretation rests on the primacy of the terms of the treaty.