This paper examines how tax aggressiveness affects the relationship between corporate social responsibility (CSR) and firm value. We posit that when other corporate behaviors are not congruent with social responsibility, investors may be skeptical of a firm's CSR efforts, attributing these efforts to corporate hypocrisy or managerial opportunism. We identify tax aggressiveness as a behavior that is socially irresponsible and inconsistent with CSR, and examine whether the market values the CSR activities of tax aggressive firms less favorably than those of non-tax aggressive firms. We find that while CSR is valued positively, CSR valuation is discounted when firms are tax-aggressive. Further analysis shows that strong corporate governance mitigates the value discount on CSR efforts of tax-aggressive firms, suggesting that the discount is partly attributable to agency costs. We also find that our results are especially pronounced in financially unconstrained firms and firms with high media coverage, suggesting that the discount is high in firms in which tax aggressiveness is likely opportunistic and whose communications strategies are indicative of corporate hypocrisy. Our study highlights the importance of aligning corporate activities with societal norms, and demonstrates the economic and social outcomes of aggressive tax strategies.