This study investigates how overall sustainability disclosures and it’s disaggregate dimensions of environment, social and governance affect market value of firms in Nigeria as an emerging economy using company’s’ specific disclosures. Tobins Q were used to proxy firm market value. The study selected 93 out of 120 non-financial firms listed on the Nigerian Stock Exchange as at 2015. Ex Post Facto research design was adopted and the secondary data was collected from annual reports of sampled firms from 2006 to 2015 through content analysis. The data were analysed with descriptive statistics, correlation analysis, principal component analysis while pooled ordinary least squares regression was employed to test formulated hypotheses. The analysis showed that overall sustainability disclosures have significant positive effects on firm value. When treated individually, environmental sustainability disclosures and corporate governance disclosures have a significant positive effect on market value of firm. The study also reveal that social sustainability disclosures have negative and insignificant effect on market value of firm. Based on these findings, the study recommended among other that companies should foster greater sustainability and long-term value creation by integrating sustainability metrics into their reporting model and strategy. Firms in Nigeria should adopt and disclose environmental friendly policies since it potray their commitment towards achieving the goal of sustainable development.