Psychogenic nonepileptic seizures (PNES) are observable changes in behavior or consciousness that are similar to epileptic seizures but are not associated with electrophysiologic changes. PNES occur in children with underlying psychological distress and are especially frequent in those with epilepsy. Because PNES are heterogeneous, comprehensive treatment tailored to each patient is required to reduce psychosocial stress. Currently, reports regarding children with PNES concomitant with autism spectrum disorder (ASD) do not exist, and effective treatment strategies for these children are lacking. In this case report, we describe a 10-year-old Japanese girl with undiagnosed ASD who developed PNES while undergoing treatment for benign childhood epilepsy with centrotemporal spikes. She exhibited hypersensitivity to sound and interpersonal conflicts caused by social communication deficits. The PNES symptoms improved shortly after our intervention, which was designed to reduce her distress caused by auditory hypersensitivity and impaired social communication, both characteristics of ASD. To the best of our knowledge, this is the first report describing PNES in a child with ASD. Our findings suggest that PNES can result from psychological distress in children with undiagnosed ASD and highlight the importance of examining ASD traits in patients with PNES.