Faces are one of the most socially significant visual stimuli encountered in the environment, whereas pareidolias are illusions of faces arising from ambiguous stimuli in the environment. Autism spectrum disorder (ASD) is characterised by deficits in response to social stimuli. We found that children with ASD (n = 60) identify significantly fewer pareidolic faces in a sequence of ambiguous stimuli than typically developing peers. The two groups did not differ in the number of objects identified, indicating that the children with ASD had a specific lack of attention to faces. Pareidolia have considerable potential as naturalistic and easy-to-create materials for the investigation of spontaneous attention to social stimuli in children with ASD.