<p>This study investigates supplier relationship management practices by translating buyers’ social sustainability orientation (SSO) into suppliers’ social outcomes. A survey of 420 firms in the production and service sectors was conducted in a developing country. Nine hypotheses were tested, and the results revealed the significant positive effects of buyers’ SSO on suppliers’ relationship management practices (i.e., selection, evaluation, and development), which enhanced suppliers’ social outcomes. However, we find firm size moderation to be positive only for the effect of buyers’ SSO on supplier evaluation. This study offers new interpretations of the role of supplier relationship management in promoting social sustainability. It also provides clearer insights for managers by illustrating the need for buyers to take more effective action beyond targeting suppliers’ evaluation metrics.</p>