This study examines the relationship between firms’ adoption of occupational safety and health (OSH) protection policies and corporate sustainability performance. Using firm-level data from five Asian markets, namely China, Indonesia, Malaysia, Thailand, and Singapore, from 2010 to 2023, we apply fixed-effects panel regression analysis. The results show that the adoption of OSH protection policies significantly enhances overall ESG performance as well as performance across individual ESG pillars. This positive impact is also consistently observed in firms’ progress toward achieving Sustainable Development Goal 11 (SDG 11). We conduct several robustness tests, including the use of lagged OSH policy adoption, application of the generalized method of moments (GMM), inclusion of institutional governance quality controls, and industry-adjusted ESG scores. Further analysis reveals that the positive relationship is more pronounced in firms with a weaker organizational climate for corporate governance and environmental responsibility. Additionally, we find that complementary initiatives such as the establishment of a task force and the implementation of whistleblower protection policies strengthen the positive effects of OSH policy adoption. Finally, gender diversity in the workplace, particularly the presence of women employees and women directors, is found to positively moderate the relationship between OSH policy adoption and ESG performance.