Introduction The concept of participation was introduced by the World Health Organisation in the International Classification of Functioning, Disability and Health, 2001. Instruments to measure participation have been developed for children and adults, but none specifically for adolescents. Adolescence is a life stage with distinct patterns of participation, and previous research has shown that young people with disabilities have poorer participation than the general population. The aim of this study was to develop a measure of participation frequency, covering all major domains, for young people with cerebral palsy (CP). CP was chosen as an exemplar because it is a significant cause of disability in young people, with affected individuals experiencing a range of different impairments of varying severity. Methods A pool of 88 items was developed using the published literature, existing measures and qualitative data from young people. The item pool was revised following expert review by 17 experts. Cognitive interviews on the items were carried out with 12 young people and 12 carers; field‐testing was then undertaken with 107 young people with CP aged 13–21 years, and 540 young people from the general population to enable item reduction and to examine reliability and construct validity. Results The content review resulted in a 92‐item draft questionnaire, content validity index of 93%. Cognitive interviews led to further wording changes. Following field‐testing, the questionnaire was shortened to 45 items. Known‐groups validity was demonstrated by correlation with impairment severity. Test–retest reliability was satisfactory for all domains. Internal consistency varied between domains. Conclusion This is the first instrument developed specifically to measure frequency of participation across multiple domains for young people with disability. Use of the questionnaire in research and clinical work will enable its properties to be better understood and its generalizability to wider groups to be clearer.