This chapter explores design’s role in addressing social sustainability in global production networks (GPNs). Using the concept of geographies of responsibility, the chapter argues that actors throughout supply chains are interdependent, their relationships embodied in the products, processes and systems that designers help to create. However, for designers in post-industrial economies, it can be challenging to identify how their decisions affect the social sustainability of those further upstream. Distant manufacturing locations and stakeholders obscured by complex, multitier supply chains present conditions seemingly beyond design’s control. Most human-centred design has focused on clients and consumers, overlooking those employed elsewhere in resource extraction, manufacturing, distribution and disposal. Social design practices could help to address this gap. Over the past decades, a rich body of work has emerged in participatory design, design for the pluriverse and design for social sustainability (D4SS). Design expertise exists in sustainable production and social sustainability, but these have yet to be combined in a meaningful way. Examples of designers acting inside, outside and alongside industry to promote social sustainability in GPNs raise questions about the limitations and opportunities for design in this context.