Attachment security provides a well-documented protective developmental function for children exposed to individual-and community-level trauma, yet the effectiveness of prevention and intervention efforts targeting attachment during adolescence has been relatively underexplored. The Connecting and Reflecting Experience (CARE) program is a transdiagnostic, bi-generational, group-based, mentalizing-focused parenting intervention developed to dismantle the intergenerational transmission of trauma and support secure attachment relationships across the developmental spectrum within an under-resourced community. This exploratory study evaluated outcomes among caregiver-adolescent dyads (N = 32) in the CARE condition of a nonrandomized clinical trial at an outpatient mental health clinic within a diverse, urban U.S. community with disproportionate trauma exposure exacerbated by COVID-19. Caregivers predominantly identified as Black/African/African American (47%), Hispanic/Latina (38%), and/or White (19%). At pre-and post-intervention, caregivers completed questionnaires regarding parental mentalizing and their adolescents' psychosocial functioning. Adolescents completed scales regarding attachment and psychosocial functioning. Results showed a significant decrease in caregivers' prementalizing on the Parental Reflective Functioning Questionnaire, improvement in adolescent psychosocial functioning on the Youth Outcomes Questionnaire, and an increase in adolescents' reports of attachment security on the Security Scale. These preliminary findings suggest that mentalizing-focused parenting interventions may be effective in fostering improved attachment security and psychosocial functioning during adolescence.