Background: Despite their high effectiveness, rehabilitation therapies can reduce the number of families with children with autism spectrum disorder (ASD) visiting clinics due to the number of treatment sessions and the long duration of treatment. The use of technological methods, such as transcranial direct current stimulation (tDCS) as one of the therapeutic interventions to improve cognitive function in rehabilitation clinics, can help reduce the duration of treatment for these children. Objectives: The present study was carried out to examine the effectiveness of tDCS in behavioral and cognitive aspects of executive functions in children with ASD. Methods: A pretest and posttest design with follow-up were used in this study. The subjects were children with high-functioning ASD aged 8 - 11 years who were selected by the convenience sampling method from occupational therapy clinics in Tehran, Iran. A total of 20 eligible candidates were included in the study according to inclusion and exclusion criteria. The subjects were randomly divided into two groups (10 subjects in each group). The intervention group received tDCS during 12 sessions of 20 minutes in the dorsolateral prefrontal cortex area, with an electrode size of 35 cm2 for 3 weeks (four sessions per week). The control group received common cognitive interventions used in occupational therapy clinics in 12 sessions of 60 minutes (one hour) for 6 weeks (two sessions per week). Follow-up was performed one month after the end of the interventions. The research instruments included the Behavior Rating Inventory of Executive Function and computer-based tests, such as the Tower of London, Wisconsin Card Sorting Test, and Stroop test. Results: The results demonstrated that tDCS, similar to cognitive rehabilitation, could affect the cognitive functions of the brain, such as executive functions, and several basic cognitive processes, such as inhibitory control, cognitive flexibility, and mental planning. Conclusions: The findings recommended using tDCS as a new intervention method to improve the cognitive function of individuals with ASD. This is due to the lasting effect of the results of this intervention as a technological instrument with faster results than other clinical interventions.