Purpose Considering that corporate social responsibility (CSR) addresses a wide range of claims from multiple stakeholders, companies must determine their CSR scope. This paper aims to examine what factors influence a firm’s decision in its scope of CSR. In exploring what factors influence CSR scope, the authors examine the relationship between a firm’s prosocial orientation and CSR and further examine its boundary conditions by the existence of CSR department. Design/methodology/approach This study uses a data set – the Social Value Survey – administered by the Center for Social Value Enhancement Studies based in the context of Korean firms. Based on 86 firm responses, statistical models were performed to test hypotheses. Findings The findings show that a firm’s prosocial orientation is positively associated with CSR scope. Further, this study shows that there is a negative moderating effect of the CSR department for the relationship between the prosocial orientation and CSR scope. Originality/value This study attempts to contribute to the extensive line of work on the antecedents of CSR by exploring the simultaneous existence of various drivers of CSR and the interplay between the drivers. And this study enhances the understanding on what factors influence the decision of CSR scope within a complex system of diverse stakeholder relationships. Additionally, this study has potentially shed light on the role of CSR departments to determine CSR scope.