Biodiversity loss and species extinction represent urgent global policy issues, exerting substantial pressure on organisations to address these challenges. Multinational Enterprises (MNEs) are increasingly incorporating biodiversity protection efforts into their reporting frameworks. Despite this trend, the external governance mechanisms driving such disclosures remain underexplored. This study examines the influence of a country's legal system, level of corruption, and cultural background on MNEs’ biodiversity and species extinction disclosures from an international perspective. Utilising a sample of the top 200 Fortune Global MNEs over a five-year period and drawing on institutional and legitimacy theories, we find that MNEs headquartered in countries with weaker legal systems and higher corruption levels provide more extensive biodiversity disclosures. Additionally, national culture is identified as a critical determinant of biodiversity disclosure. Our analysis also reveals that macroeconomic uncertainty significantly moderates these disclosures. Furthermore, the introduction of the United Nations Sustainable Development Goals in 2015 is shown to impact disclosure practices. These findings challenge the prevailing assumption that MNEs in stronger institutional environments are more responsive to external pressures. This study provides the first empirical evidence that external governance mechanisms and macroeconomic factors significantly influence biodiversity disclosures. The results, robust across alternative measures and sub-sample analyses, highlight the necessity of robust legal systems, anti-corruption initiatives, cultural sensitivity, and economic stability in achieving global biodiversity targets. These insights bear significant implications for regulators and policymakers, emphasising the need for comprehensive institutional support to enhance biodiversity protection efforts.