This longitudinal study investigates the relationship between prevention behaviors, that is, enacted violence prevention policies, and exposure to workplace violence and threats across four different high risk work sectors: psychiatry, special schools, eldercare, and the prison and probation services. Logistic regression analysis of a 1-year follow-up sample of 3.016 employees from these four sectors shows that prevention behaviors are significantly and negatively associated with self-reported exposure to workplace violence and threats—in the prison and probation services, eldercare, and in psychiatry, while no significant associations are found for special schools. The results therefore show clear sector differences with regard to the preventive effect of violence prevention behaviors. Furthermore, this multisector comparison suggests that prevention behaviors are more effective in relation to a moderate frequency of violence and threats, and that only top management prevention behavior can prevent very frequent incidents (odds ratio [OR] = 0.58). This study contributes to the literature by use of a longitudinal design and acceptable response rates, while also simultaneously investigating several high risk sectors. The results imply that when managing workplace violence in high risk areas of human service work, there should be emphasis on the use of violence prevention behaviors from top management, supervisor, and among coworkers. However, type of sector and the frequency of workplace violence should be analyzed to evaluate the potential impact of prevention behaviors.