Objective: The COVID-19 pandemic is a remarkable health crisis that enforced most of people to stay at home and quarantined for a period of time and seems to be having negative impacts on physical activity and mental health worldwide. Autism spectrum disorders, is a neurodevelopmental disorder with deficit in social interaction characteristics, relationship and stereotyped behaviors. This study was seeking to examine Iranian parents’ perceptions on physical activity for their children with autism spectrum disorder (ASD) during the COVID-19 pandemic. Methods: In this study, an explanatory qualitative methodology used and data collected via semi-structured phone interviews. The samples included 40 parents (aged 25-50 years), in Iran who had children with ASD according to the Diagnostic and Statistical Manual of Mental Disorders-5 Edition DSM-5 criteria (aged 7-12 years). Results: The results showed that the parents observed their children’s physical activity to decrease greatly contrast to before the pandemic. Parents experienced weight gain, increased anxiety, increased stereotypic behaviors, and decrease orderliness, communicative interactions, and social skills. The parents stated that, when their children were more active before COVID-19 pandemic, they were more cheerful, more adaptable and communicated more verbally. The results determined that parents believed that physical activities have positive effects on the development of their children’s physical health and behavior. They also reported some barriers to their children's participation in physical activity. Conclusion: Participate in daily physical activity and support by parents, were consequential factors to promotion their physical and behavioral health, and the development of their independent performance and quality of life during the COVID-19 pandemic.