Many formulations of contemporary globalization suggest that citizenship is being radically transformed by processes of transnationalism. And the business world is reacting to this sense of change by firms claiming to be ‘global corporate citizens’. But what exactly does global corporate citizenship mean and what are its implications? In this paper a preliminary response is made to these questions by situating corporate citizenship within the wider framework of constitutional debates about private economic law and the juridicalization of the international sphere more generally. The paper poses the issue of whether there is a quasi-constitutionalization of the international corporate sphere underway and the possible governance consequences of this process.