The objective of the paper is to empirically test the relation between carbon emissions, environmental disclosures, assurance of sustainability reports and firms’ Cost of Equity (COE) measured by an Ex-Ante proxy model. The methodological approach uses the Generalized Method of Moments (GMM) required to control endogeneity problems using a sample of 929 firms that are included in the Morgan Stanley Emerging Market Index. The data panel includes 5328 observations from 30 emerging countries covering the period 2014 to 2019. Our results indicate that firms with higher carbon emissions have higher COE, which implies that capital providers penalize highly polluting firms. Contrarily, evidence shows that firms with greater environmental disclosures, and the those who externally assure their corporate social responsibility reports decrease their COE. Our study expands the literature regarding carbon emissions and its relation with firms’ COE from an emerging market perspective covering a multi-country sample, with findings that confirm that higher emitters are penalized in terms of COE. Moreover, our research confirms in this setting the negative relation between environmental, social and governance disclosure scores and COE. Moreover, we evidence as well that the assurance of sustainability reports also promotes legitimacy and decreases information asymmetries, in the sense of reducing COE. The value of our findings is especially relevant as it may encourage listed companies in emerging countries to engage in more sustainable practices—e.g., reduce carbon emissions.