Based on a survey and content analysis of 462 peer-reviewed academic articles over the period 1990–2014, this article reviews theories related to the external drivers of corporate social responsibility and the internal drivers of CSR that have been utilized to explain CSR. The article discusses the main tenets of the principal theoretical perspectives and their application in CSR research. Going beyond previous reviews that have largely failed to investigate theory applications in CSR scholarship, this article stresses the importance of theory-driven explanations of CSR and the complementarity of different theories. The article demonstrates that the current mainstream theorizing of CSR is dominated by theories related to the external drivers of CSR and is less developed with regard to the internal dynamics. The article outlines several productive avenues for future research: the need for multi-theory studies and more research at multiple levels of analysis, particularly at the individual level of analysis. It suggests that CSR scholarship can benefit from combining theoretical insights from a range of established theoretical lenses such as institutional theory and RBV, and can gain new insights from theoretical lenses such as Austrian economics and micro-level psychological theories.