Objectives: The present meta-analysis was aimed to evaluate the effectiveness of applied behavior analysis (ABA) on behavioral problems and difficulties in children with autism spectrum disorders in Iran. Method: A total of 142 studies published from 2005 to 2013 were reviewed and eight studies were selected for meta-analysis based on applying appropriate methodologies. The eight studies involved a total of 200 participants and since each study focused on multiple autism-related problems, 28 effect sizes were obtained. The research instrument was a checklist of content analysis. Results: The overall mean effect size was found to be r=0.83 (p<0.001). The highest effect size (r=0.926) was obtained in the research of Khorramabadi, et al. (for the variable of cognitive skills) and the lowest effect size (r=0.151) was seen in the study of Mashhadi, et al. (for the variable of social development). Conclusion: The results indicate a large effect size of ABA on decreasing the problems and difficulties of children with autism spectrum disorders in Iran. In addition, greater effects are found when this method is used in long-term and with higher intensity. Therefore, it seems that ABA can be used as an appropriate treatment method for children with autism spectrum disorders.