A growing body of literature argues that improving energy efficiency is an essential step that firms must take to mitigate climate change issues. It is assumed that corporate social responsibility (CSR) in general plays a prominent role in firms’ policies, and this paper specifically investigates the effects of the individual CSR dimensions on SMEs’ energy efficiency improvement. Based on data from a sample of 146 thousand SMEs, and using logit model, and fuzzy set qualitative comparative analysis, the study reveals that high activities in social, environmental and economic CSR dimensions are associated with high energy efficiency. Specifically, the environmental CSR dimension has the highest contribution to improving energy efficiency. Furthermore, this study indicates that energy efficiency improvement can be achieved by large SMEs provided they have developed simultaneously the environmental, social, and economic CSR dimensions. In doing so, this study answers to recent calls for more research on CSR-energy efficiency relationship and addresses with greater precision why it matters to relate the role of the CSR dimensions and energy efficiency. Furthermore, this study can be of value to policymakers who are called to promote CSR practices of SMEs in order to foster their energy efficiency.