Corporate social responsibility (CSR) reporting is becoming mainstream, yet there is limited research on whether and how CSR reports communicate value relevant information. We examine the effects of CSR report readability and tone on future CSR performance and the market reaction around the release of CSR reports. Using a hand-collected dataset of Fortune 500 companies that published stand-alone CSR reports from 2002 to 2014, we find that 1-year-ahead CSR performance is positively associated with the changes in both CSR report readability and tone, suggesting that more readable text and more optimistic tone in a firm’s CSR report are indicative of better future CSR performance. Furthermore, consistent with the view that CSR reports communicate important value relevant information to the market, we document significant market reactions to report readability and tone around the release of CSR reports. Additional analyses suggest that CSR report readability enhances the association between the abnormal returns and the change in CSR report tone, and that the market reaction to CSR report readability is more pronounced for firms with lower analyst following and higher financial opacity. Taken together, our results substantiate the important roles of CSR report readability and tone in communicating future CSR performance and imparting value relevant information to the market.