CONTEXT: Transition from the pediatric to the adult health care system is a complex process that should include medical, psychosocial, educational, recreational, and vocational considerations. OBJECTIVE: In this systematic review, we aim to synthesize the evidence on transitional care interventions (TCIs) to improve the quality of life (QoL) for adolescents and young adults with childhood-onset disabilities, including neurodevelopmental disorders. DATA SOURCES: Four electronic databases (Medline, Embase, PsycINFO, and Cumulative Index to Nursing and Allied Health Literature) were searched. STUDY SELECTION: In the included studies, researchers examined TCIs for adolescents and young adults (12-24 years of age) with childhood-onset disabilities. Studies were experimental, quasi-experimental, and observational studies published in the last 26 years. DATA EXTRACTION: Two reviewers independently completed study screening, data extraction, and risk-of-bias assessment. RESULTS: Fifty-two studies were included. Five studies reported on QoL, but statistically significant improvements were noted in only 1 of these studies. Significant improvements were also found in secondary outcomes including disability-related knowledge and transitional readiness. TCIs targeted patients, families and/or caregivers, and health care providers and exhibited great heterogeneity in their characteristics and components. LIMITATIONS: Inconsistent reporting on interventions between studies hindered synthesis of the relationships between specific intervention characteristics and outcomes. CONCLUSIONS: Although there is limited evidence on the impact of TCIs on the QoL for youth with childhood-onset disabilities, there is indication that they can be effective in improving patient and provider outcomes. The initiation of transition-focused care at an early age may contribute to improved long-term health outcomes in this population.