A key strategic challenge for buying firms is to extend environmental management across the supply chain. This requires a strong environmental commitment on the suppliers' side. Adopting the supplier perspective, this study employs regression analysis with bootstrapping procedures to examine a contingent causal process model of the influence that two major green supply chain management practices widely adopted by buying firms in their relationships with suppliers, t, environmental assessment and environmental collaboration, exert on supplier environmental commitment, and the moderating effects of supplier perceived relationship attractiveness and supplier perceived justice. Results from a survey of 237 Chinese suppliers across multiple industries reveal that, while environmental collaboration positively influences supplier environmental commitment, the impact of environmental assessment is not significant. However, our moderation analysis shows that supplier perceived relationship attractiveness has a positive moderating effect on the influence exerted on supplier environmental commitment by both environmental assessment and collaboration, and our moderated moderation analysis reveals that both the above moderating effects are in turn positively moderated by supplier perceived justice. Focusing on the role of suppliers' perceptions, the study sheds light on the psychological context of the suppliers' choice to commit to the environmental management initiatives of their buying counterparts.