Internationally, increasing numbers of children are being diagnosed with an autism spectrum disorder (ASD), but there is a dearth of studies outside more affluent countries as to parents’ understanding of this condition and the support they receive. Forty-three parents were recruited from schools and clinics in Tehran and interviewed individually using a structured interview schedule. Thematic content analyses identified a lack of parental understanding about autism and its causes, along with parents’ reactions to the diagnostic process and the dearth of information available to them. The majority of parents were dissatisfied with the professional assistance provided for their children and many lacked informal support from their families. The provision of accurate information through informal parent-to-parent support seems to be the most feasible means of assisting Iranian families to adjust to having a child with ASD within the family.