Background and Purpose:The social development is a key factor in the treatment of children with ASD, for whom various methods have been proposed in terms of improving the skills and competence. The purpose of this study was to investigate the effectiveness of vestibular stimulation on social development of children with autism disorder. Method: The present study was an experimental and pre-test-posttest-follow-up study with control group. The statistical population of this study included all the special schools for autistic children in Bushehr in 2017. Then, from these schools, 30 students were randomly selected as samples and assigned to the experimental and control groups (15 per group). Vineland social maturity scale had been used for data collection. Then, an intervention was performed on the experimental group and ANOVA with repeated measure was used to analyze the data. Results: The results of this study showed that vestibular activator improves general self-help (p≤0/001), eating (p˂0/001), dressing (p˂0/001), self-direction (p˂0/001), communication (p˂0/001), verbal and linguistic skills (p≤0/001), attention to useful activities (p˂0/001), as well as purposeful movements and gestures (p˂0/001) in children with autism spectrum disorder. Conclusion:Based on the findings of this study, we can emphasize the importance of the effectiveness of vestibular stimulation on social and adaptive skills in students with autism spectrum disorder. As a result, it is recommended to use this method as an effective intervention in various educational and rehabilitation centers.