Educators have the fourth highest non-fatal occupational violence victimization rate in the United States. Few school violence policies and assault deterrents have been studied with quantitative methods to evaluate their impact on workplace violence. This study analyzed nine different written violence policies and seventeen assault deterrents to determine their impact on work-related physical assault in educational settings. Data were obtained from the Minnesota Educators' Study. Screening of 26,000 licensed educators, randomly selected from the Minnesota Department of Education's database, identified 6,180 eligible educators who were enrolled in the comprehensive Phase I study. Cases (n = 372) who reported physical assault within the last year, and controls (n = 1,116) who did not, were included in the Phase II case-control study. Multivariate logistic regression analyses were used to estimate risk of assault. Directed acyclic graphs were used to establish potential confounders and sensitivity analyses were applied to determine the potential range of bias. Overall response rates for the full study were: Phase I, 84% (78% full survey); Phase II, 84% (78% full survey). The rate of physical assault per 100 educators per year was 8.3. The multivariate analysis, after adjustment, suggested decreased risks of physical assault associated with the presence of video monitors (OR 0.72; 95% CI: 0.50-1.03), intercoms (OR 0.77; 95% CI: 0.55-1.06), routine locker searches (OR 0.49; 95% CI 0.29, 0.82), and school uniforms/dress codes (OR 0.74; 95% CI: 0.52-1.07). Decreased risk of physical assault was also associated with the awareness of policies regarding how to report sexual harassment, verbal abuse, and threat (OR 0.53, 95% CI: 0.30-0.95); assurance of confidential reporting (OR 0.67; 95% CI: 0.44-1.04); and zero tolerance for violence (OR 0.70; 95% CI: 0.47-1.04). The presence of metal detection devices (OR 18.1; 95% CI 1.05, 311.5) appeared to enhance the risk of physical assault; however confounding may be present in this low-frequency finding. Awareness of several policies and the presence of many assault deterrents may help prevent work-related physical assault. This study was an important first step in examining the impact of written violence policies and assault deterrents in educators' environments.