Thanks to advances in HIV treatment, children who were born with HIV are now living into adulthood. Services working with children and adults living with HIV have needed to adapt to support this cohort of young adults with lifelong HIV infection. Likewise, services need to meet the needs of young people who are acquiring HIV in other ways. This report considers how young people living with HIV make the transition from childhood to adulthood and, in particular, changes in services and support for young people that occur during this time. The report presents experiences described by young people living with HIV, practitioners, and parents and carers. It considers the whole young person and the full range of changes happening to an individual during adolescence and young adulthood, as well as all the services and practitioners involved at this time. The report aims to provide a broad picture of current practice around transition, and people’s experiences of this; explore and raise awareness of the challenges associated with transition; share ways in which young people and those who help guide them into adulthood address these challenges; and recommend factors to be considered when providing and developing support for young people with HIV. This project covers England. However, the consultation process included participation from some practitioners working in Wales, and one young person living in another UK country. It is hoped that this work will have relevance for, and be useful to, practitioners and services across the UK.