The mining industry remains a high-risk sector where the implementation of an Occupational Health and Safety Management (OHSMS) is critical to mitigating workplace accidents. However, the effectiveness of such system is often compromised by human behavioral factors. This study aims to analyze the influence of employee behavior-comprising knowledge, attitudes, and actions on OHSMS Implementation at a nickel mining company in Southeast Sulawesi, Indonesia. A quantitative descriptive-analytic method with a cross-sectional approach was conducted, involving 50 mining personnel as respondents. Data were processed using Partial Least Squares Structural Equation Modelling (PLS-SEM) to examine both measurement and structural models. The results revealed that worker behavior simultaneously influenced OHSMS implementation by 37.6% (R2 = 0.376). Specifically, attitude exhibited a significant positive influence (β=1.275,p=0.030), whereas knowledge showed a significant negative impact (β=-0.488,p<0.001), Interestingly, individual actions did not yield a statistically significant effect. These findings suggest that while positive attitudes are fundamental to safety compliance and procedural non-compliance. This research provides strategic insights for mining management to prioritize behavioral-based safety interventions over purely technical training.