This research article published by Elsevier Ltd., 2020Extensive land degradation is a global problem that presents a critical threat to pastoralists’ welfare in East Africa and beyond. Although the reasons for this environmental problem are complex, it is likely to be exacerbated by communal land management practices that have become suboptimal due to changes in land access and population growth. In the present paper we make initial steps towards addressing the problem by exploring socio-psychological predictors of willingness to protect communal land from degradation among Maasai pastoralists in Northern Tanzania. Based on the social identity approach and existing evidence for the role of group processes in pro-environmental action, we have developed and tested a path model predicting willingness to protect communal land. The results demonstrate that community identification is linked to willingness to act via perceived development of action-consistent group and personal norms. In addition, multiple groups analysis demonstrated a number of gender differences within the model. The results are broadly consistent with the existing social identity models of pro-environmental action, extending them into a novel context, and offering practical implications for addressing the issue of pastoralist land degradation.