Key Social Norms Take-aways This study underscores the power of individual-level empowerment to shift social norms around sexual violence. By teaching adolescent girls to assert their boundaries, resist coercion, and speak out, the intervention helped dismantle norms of silence and victim-blaming. Increased disclosure and the use of verbal resistance signaled changing expectations about girls’ agency and community-level tolerance of sexual assault.

Objectives To evaluate whether a self-defense and empowerment intervention could reduce the incidence of sexual assault and increase disclosure among adolescent girls living in high-risk, informal settlements in Nairobi, Kenya.

Methods A prospective, non-randomized controlled study design was used with 1978 girls aged 13–20 in the intervention arm and 428 in the standard-of-care (SOC) control group. Data were collected via anonymous, self-reported surveys using the ballot box method to reduce social desirability bias. Incidence rates of sexual assault were compared at baseline and 10.5 months post-intervention, and statistical analysis used Poisson regression and incidence rate ratios to evaluate changes over time.

Intervention Details The intervention consisted of six weekly two-hour empowerment and self-defense sessions, delivered by trained local female instructors. The curriculum—grounded in social learning theory and the health belief model—included assertive communication, boundary-setting, de-escalation strategies, and physical defense techniques. Girls also had access to support groups and received three refresher sessions. The SOC group received a one-time, 1.5-hour life skills session endorsed by Kenya’s Ministry of Education.

Results The annual incidence of sexual assault declined significantly in the intervention group, from 17.9 to 11.1 per 100 person-years (rate ratio = 1.61; p < .001), but not in the SOC group. Disclosure of assaults rose from 56% to 75% among intervention participants, while remaining static in the SOC group. Over half (52.3%) of intervention participants reported using their training to stop a sexual assault, with many using verbal or combined verbal and physical tactics. Conclusions: This study provides compelling evidence that a targeted, school-based empowerment intervention can significantly reduce sexual assault and shift social responses in low-resource settings. By increasing girls’ agency and changing community norms around disclosure and resistance, the program offers a scalable, cost-effective model for violence prevention globally.