Moral judgments are typically experienced as being categorically authoritative – i.e. as having a prescriptive force that (i) is motivationally gripping independently of both conventional norms and one's pre-existing desires, and (ii) justificationally trumps both conventional norms and one's pre-existing desires. We argue that this key feature is best accommodated by the meta-ethical position we call ‘cognitivist expressivism’, which construes moral judgments as sui generis psychological states whose distinctive phenomenological character includes categorical authoritativeness. Traditional versions of expressivism cannot easily accommodate the justificationally trumping aspect of categorical authoritativeness, because they construe moral judgments as fundamentally desire-like. Moral realism cannot easily accommodate the aspect of inherent motivational grip, because realism construes moral judgments as a species of factual belief.