Many autistic youths experience restricted school participation. The present study investigated the influences of youth, family and school factors on autistic youths' school participation. Parents of 200 Dutch autistic youths (age range: 4-16 years, M[subscript age] = 12.23 years, SD[subscript age] = 2.93 years) filled in questionnaires in a national survey for autistic individuals, reporting the school participation, age and autistic traits of their child, parents' education level and self-efficacy for supporting their child's schoolwork, and the impact of problems their child experienced with the physical and social environments of the school. Multivariate linear regression analysis using imputed data revealed that among the six predictor variables, only the impact of problems autistic youths experienced with the physical environment of school was negatively associated with their school participation. This study provided support for the essential role of the school environment in predicting autistic youths' school participation, indicating that problematic aspects in the school environment could have a greater impact on autistic youths' school participation than youth factors or family factors. This highlights the need to create a more accommodating environment at school, where autistic youths can participate easily and comfortably.