ObjectiveTo develop a patient-centred outcome measure (PCOM) for use with children and young people accessing National Health Service (NHS) wheelchair and posture services. Identifying and addressing outcomes of most importance to young wheelchair users (≤ 18 years) will help services maximise the benefits achievable within available resources.MethodsA mixed-methods approach was used, involving questionnaire surveys and qualitative interviews, and building on previous work identifying how young wheelchair users define health-related quality of life (HRQoL). Framework analysis was used to analyse the interview transcripts. Survey questionnaires seeking views on the importance of a range of outcomes were completed by 21 young wheelchair users or their parents. Subsequent face-to-face interviews with 11 parents or dyads of parents and young wheelchair users explored these responses and identified novel outcomes. Interviewees also scored and recorded satisfaction levels for their key outcomes.ResultsAll outcomes proposed in the survey were rated as ‘extremely important’ by at least one respondent, as were additional outcomes uncovered in the qualitative data. In consultation with the service providers and service users, the Wheelchair outcomes Assessment Tool for Children (WATCh) was developed to allow service users and providers to identify, score and monitor individual users’ most important outcomes. The final WATCh tool comprises 16 outcome options, of which service users select five to be monitored. The tool will be used to measure key outcomes identified by service users before and after wheelchair provision.