Transition from pediatric to adult care for adolescents and young adults (AYAs) with chronic illness affects the entire family. However, little research has compared AYA and parent experiences of transition. Using Sandelowski and Barroso’s method, the aim of this metasynthesis was to summarize findings of qualitative studies focusing on the transition experiences of AYAs and their parents across different chronic physical illnesses. PubMed, EMBASE and CINAHL were searched followed by forward and backward citation searching. Two authors completed a two-step screening process. Quality was appraised using Guba’s criteria for qualitative rigor. Study characteristics and second order constructs were extracted by two authors and an iterative codebook guided coding and data synthesis. Of 1,644 records identified, 63 studies met inclusion criteria and reflect data from 1,106 AYAs and 397 parents across 18 diagnoses. Three themes were synthesized: transition is dynamic and experienced differently (differing perceptions of role change and growth during emerging adulthood), need for a supported and gradual transition (transition preparation and the factors which influence it) and liminal space (feeling stuck between pediatric and adult care). While AYAs and parents experience some aspects of transition differently, themes were similar across chronic illnesses which supports the development of disease agnostic transition preparation interventions. Transition preparation should support shifting family roles and responsibilities and offer interventions which align with AYA and family preferences.