The value relevance of corporate sustainability performance (CSP) has been studied from different theoretical perspectives, yielding inconclusive evidence. Therefore, it is imperative to revisit corporate sustainability performance relevance for investors. This study explores the value relevance of corporate sustainability performance by studying the impact that the quality of sustainability reporting has on it. It employed the panel data of 247 firms from 2012 to 2016 for the best 30 green capital markets ranked by the Global Green Economy Index. The results indicated that investors value corporate sustainability performance (achieved through social, economic, and corporate governance dimensions only) and the quality of sustainability reporting. However, the environmental dimension of CSP lacks financial materiality for investors. Furthermore, the quality of sustainability reporting plays an instrumental role in the value relevance of the corporate governance dimension because it is perceived as an alternative corporate governance mechanism by investors. The findings are useful for practitioners, regulators, and other stakeholders interested in understanding the value relevance of corporate sustainability performance and quality of sustainability reporting.