This correlational study assessed how families of children with mental illness perceived the levels of support they received from informal and formal resource providers and the associations between perceived support and child outcomes. Adult caregivers ( N = 904) of youth receiving public mental health care services were administered the Family Caregiver Perceptions of Support Scale developed by the authors to assess family caregiver perceptions of support prior to and at termination of services. Factor analysis identified three types of caregiver anticipated supports: informal support resources , support for treatment plan influence , and health care resources . The domains were significantly and positively associated with one another but did not uniformly correlate with youth mental health outcomes. The study provides preliminary evidence that treatment gains in youth mental health outcomes are observed when caregivers perceive support in treatment processes. Suggestions for future research are made, stressing the importance of caregivers and providers working together and describing needs related to future scale improvements.