Abstract Sexually transmitted infections (STI) continue to be a major public health problem for Black girls in the United States. Each year 1 in 4 Black girls, 14-19 years-old acquires an STI, placing them at risk for poor sexual and reproductive health outcomes (SRH) (i.e., pelvic inflammatory disease, infertility, HIV/AIDS). In Chicago, STI rates are highest among 13- to 29-year-old Black girls and they represent 56% of new HIV diagnoses, compared to other racial groups, making adolescence an exceptionally vulnerable period. These racial disparities require new and innovative strategies to reduce Black girls' negative SRH outcomes. Familial protection is seen as critical to mitigating risk, particularly exposure to sexual violence which is linked to girls' HIV/STI risk. Interventions that strengthen family relationships and communication as strategies to protect Black girls have demonstrated success improving Black girls SRH outcomes. Yet, with few exceptions, these programs engage only female caregivers, whereas male caregivers may amplify the protective effects of families on Black girls' SRH. We systematically adapted IMARA (an evidence-based program designed for Black girls and their female caregivers) to create IMARA for Black Male caregivers and Girls Empowerment (IMAGE), adding drivers of structural violence (i.e., stereotype messaging and lack of protection) aligning with the Becoming a Sexual Black Woman framework and the Health Disparities Research Framework. Preliminary data (interviews, focus groups, theatre, and pilot testing) with Black girls, male and female caregivers justify the proposed randomized control trial (RCT). We will simultaneously conduct an effectiveness RCT with individual- level randomization and examine implementation processes at five community-based organizations. Aim 1 is to conduct a 2-arm RCT (IMAGE vs. a health promotion control) with 372 14-18-year-old Black girls and their male caregivers and compare girls' sexual risk behavior (condom use, sexual debut, and sexual partners) and STI incidence at baseline, 6- and 12-months. We hypothesize Girls in IMAGE will report more condom use, later sexual debut, fewer sexual partners, and have lower STI incidence at 6- and 12- months (primary outcome) compared to the control group. Aim 2 is to examine change in the theoretical mechanisms posited by the Becoming a Sexual Black Woman. Aim 3 is to identify processes, barriers, and facilitators associated with primary outcomes to inform future implementation into community-based organizations. The long-term significance and impact of this application is high. By including Black male caregivers in the protection of girls, this study leverages a long-neglected yet important resource in Black girls SRH, thereby amplifying the protective effects of family-based programs and pushing the science of health disparities forward.