ABSTRACTBullying at work has profound effects on both the individual and organization. We aimed to determine if organizational psychosocial safety climate (PSC; a climate specific to worker psychological health) could reduce workplace bullying and associated psychological health problems (i.e., distress, emotional exhaustion, depression) if specific procedures were implemented (PSC enactment). We theorized that the PSC enactment mechanism works via psychosocial processes such as bullying mistreatment climate (anti-bullying procedures), work design (procedures reduce stress through work redesign), and conflict resolution (procedures to resolve conflict). We used two-wave national longitudinal interview data from 1,062 Australian employees (Australian Workplace Barometer project) and structural equation modelling to explore relationships over 4 years. PSC Time 1 predicted enacted PSC and reduced bullying 4 years later. PSC Time 1 was indirectly negatively related to poor psychological health Time 2 through enacted PSC and bullying. Bullying Time 1 also gave rise to procedures which in turn reduced bullying Time 2. Our findings suggest a multi-component approach to prevent or reduce bullying. Procedures (to reduce psychosocial hazards) that emerge in a high PSC context are more comprehensive than those triggered by bullying (reactive procedures), and can therefore be more effective in reducing worker mistreatment. Building PSC and a strong climate for psychological health, and enacting PSC is fundamental to bullying prevention.