Research has shown that implementation of corporate social responsibility (CSR) practice represents a considerable challenge for small and medium‐sized enterprises (SMEs). This research conceptualises the dimensions and contingencies of CSR in SME supply chains. Drawing on institutional theory and stakeholder theory, we investigated the degree of importance and implementation of CSR practices in SMEs. A large‐scale questionnaire survey with SMEs in manufacturing sectors and panel discussions were conducted in South Korea. The findings indicate that SMEs tend to focus on explicit CSR practices that can be easily identified by their customers. Consistent with this, stakeholder and institutional pressures were valid in the performance of CSR practices, but largely biased to customers, government, and regulatory pressures. Based on institutional theory and stakeholder theory as overarching theoretical lenses, this research contributes to a fuller understanding of the dimensions of CSR practices in the supply chains from an SME perspective. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment