Cystic fibrosis (CF) is Australia's most common life limiting genetic condition, characterised by declining health and quality of life (QoL) over time. Despite improvements in treatment, there remains no cure. Adolescents and young adults (AYAs) with CF experience broad impacts to psychosocial functioning and QoL, as well as major transitions in care, all at a time of significant developmental change. The importance of developmentally tailored approaches to youth health care and self-management for young people with CF are well understood. However, to date, models of youth specific self-management have been lacking and motivation for young people with CF has not been well explored. This qualitative study, based on a social constructionist epistemological framework, addresses this gap. A total of 21 AYAs aged 15-30 years were recruited through one paediatric and one adult Australian CF centre.Demographic, clinical and distress data were captured to describe health complexity. Semi-structured interviews were audio-recorded, transcribed and analysed using thematic analysis. Participants were representative of Australian AYAs with CF by demography and clinical status. Alarmingly, over a third reported clinically significant distress. Two themes emerged. The first Identified impacts to motivation and self-management resulting from the challenges of managing CF, life and care. These included time and competing priorities, changing health statis, mental health, social factors, unmet needs and health system complexity. The second identified factors that support motivation including: achievement, meaning and purpose; consequence avoidance; and accountability. These results illustrate the importance of AYA specific, theoretically founded, holistic self-management models which extend beyond current theoretical approaches that aim to understand behaviour change or address barriers, in isolation from motivation. Improved approaches to care based on these findings are essential to foster positive behavioural change, support self-management and foster the best health outcomes for young people living with CF.