Background: Comprehensive health education in schools can effectively prevent drug use and related outcomes, but successful implementation remains challenging. Contextual determinants, including intervention-setting compatibility, focus on the intervention, available resources, and leadership support, influence implementation success. This study investigates the impact of multilevel contextual determinants on Michigan Model for Health: (MMH) curriculum fidelity. Methods: High school health teachers across Michigan (N = 171) participated in an MMH implementation survey. We used structural equation modeling to investigate the relative contributions of contextual determinants to implementation fidelity while also permitting the determinant factors to covary. Results: The models demonstrate a good fit with the data (structural: X[superscript 2] = 51, df: 34, p = 0.03; RMSEA: 0.06, 95% CI: 0.02, 0.08; CFI: 0.98). Results indicate that the context latent factors individually were associated with fidelity. Examined together, we found significant covariance between the latent factors, but only resources predicted fidelity. Implications for School Health Policy, Practice, and Equity: School health policy and practice benefit from sufficient resources to support prevention curriculum implementation. Insufficient resources exacerbate existing barriers in low-resource communities, leading to unequal intervention implementation and widening health disparities. Conclusions: Our results indicate that while contextual determinants are interrelated, sufficient resources are foundational to successful implementation.