Background: The increasing prevalence of hypertension in adolescents aged 15-24 years, reaching 9.3%, demands holistic preventive strategies beyond conventional education. This study aims to evaluate the effectiveness of Health Belief Model (HBM)-based educational interventions on changing primary hypertension prevention behavior in adolescents. Subjects and Method: This quasi-experimental study with a Non-Equivalent Control Group Pretest-Posttest Design involved 120 students (60 intervention, 60 control) in the Dinoyo PHC working area. The sampling technique used multi-stage cluster random sampling. Variables were measured using structured questionnaires and clinical measurements, then analyzed using ANCOVA and Partial Least Squares Structural Equation Modeling (PLS-SEM). Results: The HBM intervention was significantly effective in transforming hypertension prevention behavior (p < 0.001; effect size η2 = 0.380) compared to standard education. Structural analysis showed that self-efficacy was the most dominant predictor (β = 0.51) in mediating the adoption of a healthy lifestyle. Conclusion: HBM intervention contributes significantly to fostering early healthy behavior habituation. Policy implications suggest integrating HBM modules into School Health Unit (UKS) programs