Drawing on insights and methods from International Law, International Relations and Linguistics, the article untangles the discursive legitimation efforts of international adjudicative bodies. Combining supervised learning methods, corpus methods and Critical Discourse Analysis it analyses the language of legitimation in the jurisprudence of the International Court of Justice and the World Trade Organization’s Appellate Body, over a period of twenty years (1996-2016). In so doing, the article cuts across disciplinary divides and offers a novel and empirically informed perspective to ongoing debates on the discursive legitimation of international adjudicative bodies.