Since the 1990s, transnational activist networks dedicated to improving social and environmental conditions in global value chains (GVCs) have developed through connections between social movements in Southern and Northern Hemispheres, with the aim of establishing a ‘chain of responsibility’ between lead firms operating at the market end of GVCs, and the suppliers and workers performing raw material production and manufacturing at the upstream end of the chains. This contribution addresses the phenomenon in three steps. The first section discusses various ways in which activist networks have been accounted for in the GVC literature, with particular attention to the neo-Gramscian view of ‘contested governance’ in GVCs. The second highlights key features of GVC-based activism in its emergence, operational modes and strategic orientations. The third section analyses the dialectics at work both within global activist coalitions and between these coalitions and their campaign targets, around the ways in which social-environmental outcomes are and should be addressed in GVCs.