This doctoral dissertation examines the EU consumer perspective on externalities of production in global value chains (GVCs). Whether as part of the discourse on development or global economic governance, externalities of production are a long-standing issue that has been problematised not only by lawyers but also by economists, anthropologists, sociologists and social scientists at large. In the legal field, the analysis has struggled to contextualise consumer law and policy together with the peculiarities of GVCs as a distinct model of business organisation characterised by contractualisation of processes of production. The thesis argues that contractualisation of production establishes a relationship between consumers and processes of production, also in relation to externalities. Such a relation is not mirrored either by the voluntary self-regulation through which enterprises regulate externalities nor by EU consumer law. The present dissertation addresses this matter and argues that EU consumer law limits the involvement of consumers in the process of self-regulation that leading enterprises of GVCs undertake to prevent and/or remedy externalities of production and that results into a unilateral exercise of epistemic authority. The exercise of epistemic authority is favoured by a ‘communication paradigm’ framing EU consumer law, according to which consumer claims’ on sustainability and externalities of production depend on the content of the communication consumers receive prior or via the contract. This paradigm prevents consumers involvement, in all phases of the contractual relationship, in the definition of a legal episteme of sustainability in line with the core constitutional principles and values as enshrined in the EU Treaties and constitutional charters of member states. The final part of the thesis suggests that the limits deriving by the communication paradigm can be overcome by the CJEU that, by relying on the principle of effectiveness can integrate the communication paradigm with a consumer perspective on externalities of production in the post-contractual phase.