This study examined the psychometric properties of the Therapeutic Alliance Scale for Caregivers and Parents (TASCP) in a sample of 209 caregivers whose children (4–13 years of age) presented with disruptive behavior problems to a publicly funded outpatient mental health clinic in San Diego County. Information about therapeutic alliance was collected from caregivers, children, and their therapists across the course of therapy (up to 16 months). Results support the reliability, temporal stability, convergent validity, and discriminant validity of scores on the TASCP. The multilevel factor structure of this new measure was consistent with the parallel child-report version, with 2 within-level factors and 1 between-level factor. Furthermore, predictive validity was strong, with stronger caregiver-reported alliance associated with less treatment dropout, more sessions attended, and greater satisfaction with perceived improvement.