<![CDATA[Background: Adolescents are a priority population for HIV prevention because knowledge, decision-making capacity, and perceptions of risk are still evolving during this developmental stage. Family engagement may enhance protective behaviors by strengthening communication, supervision, emotional support, and adolescents’ confidence in avoiding high-risk situations. Objective: This study aimed to evaluate the effectiveness of a family-based HIV prevention intervention in improving sexual risk prevention behavior among adolescents in Bandung Regency, Indonesia. Methods: A quasi-experimental study with a pretest-posttest control-group design was conducted among 350 adolescents aged 16–18 years. Participants were assigned to an intervention group (n = 175) or a control group (n = 175). The intervention consisted of three weekly family-based educational sessions involving adolescents and caregivers, while the control group received standard HIV prevention information through leaflets. Outcomes were assessed using the Sexual Behavior Abstinence and Avoidance of High-Risk Situation Questionnaire, which measures self-efficacy, behavioral intention, and perceived benefit. Data were analyzed using paired-sample t-tests and analysis of covariance (ANCOVA). Results: The intervention group demonstrated a significant increase in overall HIV prevention behavior scores from 43.81 ± 5.40 at baseline to 58.48 ± 4.20 after the intervention (p < 0.001). Although the adjusted between-group difference in total scores was not statistically significant (p = 0.078), significant improvements were observed in self-efficacy, behavioral intention, and perceived benefit (all p < 0.05). Conclusion: Family-based HIV prevention interventions effectively strengthen psychosocial determinants associated with protective behaviors among adolescents. Integrating family participation into school- and community-based health promotion programs may support culturally appropriate HIV prevention strategies in Indonesia.]]>
