Firms engage in corporate social responsibility (CSR) because they consider that some kind of competitive advantage accrues to them. We contend that resource-based perspectives (RBP) are useful to understand why firms engage in CSR activities and disclosure. From a resource-based perspective CSR is seen as providing internal or external benefits, or both. Investments in socially responsible activities may have internal benefits by helping a firm to develop new resources and capabilities which are related namely to know-how and corporate culture. In effect, investing in social responsibility activities and disclosure has important consequences on the creation or depletion of fundamental intangible resources, namely those associated with employees. The external benefits of CSR are related to its effect on corporate reputation. Corporate reputation can be understood as a fundamental intangible resource which can be created or depleted as a consequence of the decisions to engage or not in social responsibility activities and disclosure. Firms with good social responsibility reputation may improve relations with external actors. They may also attract better employees or increase current employees’ motivation, morale, commitment and loyalty to the firm. This article contributes to the understanding of why CSR may be seen as having strategic value for firms and how RBP can be used in such endeavour.