This systematic review assesses the effectiveness and safety of aripiprazole for treating attention deficit hyperactivity disorder (ADHD). The databases of PubMed/MEDLINE and Google Scholar were searched. All the controlled and non-controlled trials of aripiprazole for the treatment of ADHD were included. The latest search was conducted in March 2013. The quality of studies was assessed, and the efficacy and adverse effects were evaluated. Out of 34 relevant retrieved titles, only 2 articles reported randomized double blind controlled clinical trials. None of the controlled trials reported that aripiprazole was effective. However, a very high rate of adverse effects such as weight gain, sedation, and headache were reported. No well-controlled clinical trial was found. In contrary to non-controlled studies, the findings of controlled trials do not support the effectiveness of aripiprazole for treating ADHD. In addition, the high rate of adverse effects suggests that more controlled trials require to be conducted to reach a conclusion.