Caregiver engagement and participation in community-based outpatient treatment services for adolescents is generally poor, which is problematic given the integral role of caregivers prescribed by evidence-based treatments across orientations. The current study explores the psychometric and predictive properties of a set of caregiver engagement techniques distilled from family therapy, used by community clinicians in routine care. It highlights relational engagement interventions and adds to growing work distilling core elements of family therapy. The study examined caregiver engagement techniques observed in 320 recorded sessions and outcome data from 152 cases treated by 45 therapists participating in one of three randomized trials investigating delivery of family therapy for adolescent behavior problems in community settings. Construct and predictive validity of caregiver engagement coding items were analyzed to understand the degree to which they cohered as a single factor and predicted outcomes in predictable ways. Results demonstrated item reliability and construct validity of a Caregiver Engagement Techniques factor. Greater use of these techniques was associated with decreased adolescent substance use. Unexpected results suggested greater use of techniques was associated with worsening internalizing symptoms and family cohesion per youth-report only. Post-hoc analyses revealed additional complexities in the association between engagement techniques and outcomes. Caregiver engagement practices tested in the current study represent a unified treatment factor that may contribute to positive therapeutic outcomes for adolescents in some clinical domains. Further research is needed to understand predictive effects.