The prevalence of autism spectrum disorders is believed to be higher than that of other conditions, such as Down syndrome or diabetes, yet few studies have explored the ideas lay people have about autism. Semi-structured interviews were used to explore how 10 lay people with no knowledge or experience of autism conceptualised autism. Interpretative phenomenological analysis and discourse analysis illuminated four discourses: (1) autism as transgressing normative expectancies; (2) dependency and functional ability discourse; (3) autism and the discourse of mental status; (4) autism and explanatory discourses. Participants demonstrated clear views (although not necessarily correct) about the nature, origins and manifestations of autism. They drew upon their understanding of normal child development to make these assessments and they made judgements about the ability of individuals with autism to attain social independence. It is recommended that interactions between lay people and people with autism may help develop positive conceptualisations of autism.