We examine the extent to which corporate social responsibility (CSR) disclosure practices influence the likelihood of inclusion in a major corporate sustainability index (the DJSI World Index) above and beyond CSR performance. Using a propensity-matched sample based on multiple dimensions of CSR performance, we find that credibility enhancers such as the issuance of CSR reports, the assurance of CSR reports, the use of a reputed assurance provider, and the adoption of the Global Reporting Initiative standards have considerable influence on the likelihood of inclusion in the DJSI World Index. Further analyses show that the inherent credibility of CSR disclosures such as the length of CSR reports, the disclosure of uncertainties about CSR activities and the use of charts and figures are also positively associated with the likelihood of future inclusion in the DJSI World Index. However, the use of images about nature in CSR reports is seen as greenwashing which decreases the likelihood of inclusion in the DJSI World Index. Our results inform stakeholders on the importance of how CSR performance is reported for sustainability index inclusion decisions.