Autistic young people often struggle to cope with the daily demands of school and are likelier to experience poorer wellbeing and educational outcomes than their non-autistic peers. Among other factors, this may be because mainstream settings are unsuitable for individuals' sensory needs. Evidence suggests the unpredictable multi-sensory nature of school can elicit sensory distress, adversely affecting behaviour and learning. However, existing literature has primarily taken a top-down deductive approach and largely neglected autistic voices. The present study, therefore, employed a participatory approach and photo-voice semi-structured interview method to explore autistic students' sensory experiences in a mainstream secondary school in the U.K. The sample consisted of six students aged 12-16 years with a clinical diagnosis of autism attending a state comprehensive school in Suffolk, U.K. Through reflexive thematic analysis, three main themes were identified: (1) impact of the school environment; (2) the importance of safe spaces and (3) levels of support and understanding. This study's findings suggest autistic students are routinely overstimulated, overwhelmed and lack adequate support to overcome sensory barriers in mainstream settings. This study has implications for further participatory research and inclusive practice to ensure better educational experiences and outcomes for autistic young people.