This study examines the impact of ESG (Environmental, Social, and Governance) disclosure on market uncertainty, with a focus on the moderating effect of carbon disclosure. Using a 10-year dataset from non-financial U.K. companies listed on the FTSE All-Share index (2012-2021), the research employs four regression methods to analyze the relationship between ESG and carbon disclosure, and market uncertainty. The findings indicate a significant negative relationship between ESG disclosure and market uncertainty, aligning with the Information Asymmetry Theory. Additionally, carbon disclosure is found to amplify this negative relationship, supporting the Signaling Theory. The study enriches the literature on sustainability reporting by extending Information Asymmetry and Signaling Theories to U.K. non-financial firms and emphasizing the need for transparent ESG reporting. The results have implications for managers, investors, regulators, and policymakers, highlighting the importance of ESG and carbon disclosure in reducing the cost of capital, enhancing firm value, and boosting investor confidence. The study also calls for more research on sustainability disclosure and suggests that stakeholders should use these disclosures to evaluate a firm's impact and contribution to the Sustainable Development Goals (SDGs).This study examines the impact of ESG (Environmental, Social, and Governance) disclosure on market uncertainty, with a focus on the moderating effect of carbon disclosure. Using a 10-year dataset from non-financial U.K. companies listed on the FTSE All-Share index (2012-2021), the research employs four regression methods to analyze the relationship between ESG and carbon disclosure, and market uncertainty. The findings indicate a significant negative relationship between ESG disclosure and market uncertainty, aligning with the Information Asymmetry Theory. Additionally, carbon disclosure is found to amplify this negative relationship, supporting the Signaling Theory. The study enriches the literature on sustainability reporting by extending Information Asymmetry and Signaling Theories to U.K. non-financial firms and emphasizing the need for transparent ESG reporting. The results have implications for managers, investors, regulators, and policymakers, highlighting the importance of ESG and carbon disclosure in reducing the cost of capital, enhancing firm value, and boosting investor confidence. The study also calls for more research on sustainability disclosure and suggests that stakeholders should use these disclosures to evaluate a firm's impact and contribution to the Sustainable Development Goals (SDGs).