Introduction: The plantation sector is ranked third in occupational accidents in Indonesia by 2022 (17.3%), with cases rising by 18–20% annually. A major contributing factor is workers’ limited knowledge of Occupational Safety and Health (OSH). This study evaluates the effectiveness of module-based OSH education and cadre formation in improving workers’ knowledge, attitudes, and behaviors, as well as in reducing occupational accidents and diseases among workers. Methods: This research was conducted over six months, from February to August 2024, in palm oil companies located in Central Kalimantan and South Kalimantan Provinces, Indonesia. A quasi-experimental method was employed using purposive sampling. A total of 60 respondents were recruited based on predetermined inclusion criteria. The sample size was determined through statistical calculations at a 95% confidence level. Results: The intervention resulted in a significant improvement in OSH indicators. The proportion of workers with good OSH knowledge increased from 41.67% to 80.00% (p < 0.001), positive OSH attitudes rose from 46.67% to 61.67% (p < 0.001), and good OSH practices improved from 41.67% to 66.67% (p < 0.001). The incidence of occupational accidents declined markedly from 66.7% to 10.0%, and the incidence of reported occupational diseases decreased from 43.3% to 33.3%. Conclusion: Module-based OSH education and cadre empowerment effectively enhance OSH knowledge, attitudes, and behaviors while reducing occupational accidents and diseases in oil palm plantations. This model offers a sustainable and scalable approach to improving workplace safety and health, which other plantation sectors can adopt to support long-term occupational health improvements. © 2025, Occupational Health and Safety Society of Nepal. All rights reserved.