Purpose-The purpose of this paper is to systematically review the academic literature on non-governmental organizations' (NGOs) role in sustainable supply chain management (SSCM) to develop a conceptual framework. Design/methodology/approach-This paper conducts a systematic literature review through an analysis of 47 papers identified from peer-reviewed academic journals published from 2002 to 2020. Findings-Adopting social movement theory and based on thematic findings, this paper proposes four steps and six propositions in the process of NGOs fostering SSCM. These include relative deprivation, political opportunities, resource mobilization and collective action, based on which we developed a conceptual framework regarding the role of NGOs in improving sustainability in supply chains. The proposed conceptual model opens a new avenue of research in NGO literature and several directions for further research. Originality/value-This study may be the first to provide a systematic review of NGOs' role in improving sustainability in supply chains. Moreover, by borrowing the social movement theory from sociology, this paper able to propose a new conceptual framework with a research agenda so as to deepen the understanding of the phenomenon and provide directions for future research.