Transition between Child and Adolescent Mental Health Services (CAMHS) and Adult Mental Health Services (AMHS) can be stressful for the young person and family alike. Previous reviews have focused on specific aspects of transition or perspectives of young people, or have not used systematic approaches to data identification and analysis. The objective of this review was to develop the understanding of the transition between CAMHS and AMHS by systematically identifying and synthesising evidence regarding professionals' and parents/carers' perspectives. A systematic search in July 2018 was conducted on Medline, PsycINFO and CINAHL. Google Scholar and references of selected articleswere also searched. Papers were included if they presented empirical qualitative research in peer-reviewed journals with a primary focus on experiences of parents/carers and/or mental health professionals in relation to adolescents making the CAMHS-AMHS transition. Data were extracted from each full-text paper. The quality of included studies was appraised using an expanded Critical Appraisal Skills Programme (2018) tool, and studies' results were synthesised using meta-ethnography. Fourteen studies of variable quality were identified. Four main third-order constructs were developed through synthesis: (a) Service cultures; (b) Service resources and gaps; (c) Working relationships between the services; and (d) Leaving secure relationships for new ones. Professionals and parents experience adolescents' transition from nurturing and comprehensive CAMHS to more individualistic AMHS as having many barriers. There is desire for better preparation for transition between services and relationships, more joint working and better CAMHS-AMHS communication. AMHS service gaps exist, for example for those with neurodevelopmental conditions.