This study investigated the relationship between ESG reporting and firm value with emphasis on the moderating effect of accounting information timeliness in the relationship using the value-enhancing theory as a theoretical bedrock. Secondary sources were employed to obtain data from 76 nonfinancial listed firms in Nigeria covering the period 2011–2023. The study employed Weighted Least Squares regression to address heteroscedasticity concerns. The study found mixed results because environmental and governance disclosures had a significant effect on firm value, whereas social disclosures did not. Again, accounting information timeliness had a significant negative effect on firm value, suggesting that the timeliness quality sent signals to investors about reliability of the report and value of a firm. The study concluded that accounting information timeliness made investors to have confidence in sustainability report and was therefore a good moderator of any negative impact of sustainability reporting on firm value. The need to balance accounting information timeliness with sustainability reporting was suggested, as investors can penalize firms that delay in providing accounting information.