There is an abundance of literature on health-related outcomes for children and young people with Prader-Willi syndrome and on their lived experiences as well as on their caregivers'. However, little is known about the experiences of education practitioners when providing for them. This study gathered in-depth evidence of the lived experience of school staff in two secondary specialist schools, on (1) perceptions of functioning and participation of young people with Prader-Willi syndrome in the setting and (2) how prepared they felt to support them in achieving full participation, including challenges faced. Semi-structured interviews were conducted with six school staff and transcripts were analysed both deductively (using the ICF classification system) and inductively. School staff perceive the needs of these pupils as mostly related to their body functions, in alignment with a medicalised understanding of disability. However, they recognise the key role of environmental modifications to address these. Staff feel mostly unprepared and perceive their training as limited. Despite wide recognition of the need to conceive disability holistically, medicalised understandings are still present. Training from a biopsychosocial perspective is needed. Future research should address the development of core sets of ICF codes for people with Prader-Willi syndrome.