This study examines the relationship between governance sustainability disclosure and the market value of listed oil and gas firms in Nigeria. Utilizing an ex post facto research design, secondary data from the financial reports of eleven oil and gas firms listed on the Nigerian Stock Exchange (NSE) between 2019 and 2023 were analyzed. The study employs the Ordinary Least Squares (OLS) regression method to determine the effect of governance sustainability disclosure on market value. Findings indicate that board remuneration and board size exhibit a positive but insignificant relationship with market value, suggesting that governance disclosures in these areas do not strongly influence firm valuation. Conversely, the audit committee demonstrates a significant negative effect on market value, implying that stringent governance oversight may be perceived as a response to governance inefficiencies, potentially eroding investor confidence. The study concludes that governance sustainability disclosures alone may not be a primary determinant of market value in the capital-intensive oil and gas sector. It recommends that firms enhance governance strategies beyond compliance to foster investor confidence and long-term financial performance