Peer delivered, family-to-family (F2F) support-defined as the provision of outreach, engagement, knowledge, care coordination, and support to family members of children and youth with mental health challenges-is a rapidly growing and needed component of the service array. Progress is occurring toward greater specification of program models and core competencies for the parent support providers (PSPs) with lived experience providing these services; however, strategies to inform quality improvement and ensure accountability are lacking. The Family Journey Assessment (FJA), completed by PSPs and family members, fills this gap by tracking caregiver progress toward self-advocacy and self-efficacy. Analyses of 436 FJAs showed a reliable 3-component structure, reflecting progress in the recognition of needs, collaboration to access help from formal and natural supports, and activation of skills to cope with stress, enhance resilience, and develop and carry out plans of care. PSP feedback provided strong evidence for relevance and usability. Examination of FJAs at baseline and follow-up provides one of the first reports showing significant improvement in key indicators of benefit of F2F for participating families. The FJA holds promise as a measure of the impact of F2F services on key goals and as a way to identify benchmarks for focused and individualized peer-to-peer support depending on the family's level of need. (PsycINFO Database Record (c) 2019 APA, all rights reserved).