This paper enquires into an alternative foundation for investor rights within international investment law, linked to a theory of deliberative democracy and a procedural right to be heard. Drawing upon historical and contemporary accounts within political theory, the paper advances a justification for investor protection that is limited principally to procedural protections associated with the Latin maxim audi alteram partem (“hearing the other side”). After outlining the foundations for this approach in English administrative law and political theory, the paper turns to selected arbitral awards in order to illustrate how a right to be heard would be advantageous to all the interests involved. The author proposes bringing together theory, history and practice in order to ground a theory of investor protection that better reconciles power, politics and democracy.