Extended school nonattendance has been identified across previous literature as problematic for autistic pupils and prevalence rates are considerably higher for this cohort than their neurotypical peers. The neurodiversity paradigm calls for a shift towards qualitative and participatory research methodologies, which was identified as a suitable approach for the current study to understand autistic young people's lived experiences. This participatory inquiry adopted a flexible and reflective approach with two autistic adolescents who had extended school nonattendance and aimed to explore how Kas and Z experienced this and described effective support to meet their needs. Adolescents' perspectives were supported by three parental viewpoints. The participatory design allowed participants to identify key themes of effective support: a nuanced relationship with time; internal processes of control and motivation; relationships and safe environments; perspectives around their diagnosis of autism. A thematic map was developed to highlight the interaction between adolescents' perspectives and parental viewpoints and the superordinate, researcher-identified theme of Understanding and Acceptance of Individual Lived Experience of Autism. The methodology and themes suggest considerations for professionals to develop practice to support autistic pupils who experience extended school nonattendance. Implications for future research are discussed.