Introduction: Since the anxiety is one of the effective factors in stuttering, the present study was examined the effect of Transcranial direct current stimulation (tDCS) on anxiety and the severity of stuttering in stammering adolescents.Materials and Methods: The present study adopts pre-test and post-test quasi-experimental design with two experimental and one control groups. For this purpose, after applying input and output criteria, 30 stuttering adolescents were selected by convenience sampling method, and were divided into experimental and control groups, randomly. During 10 sessions, one of the experimental groups (EG1) includes 15 participants were experimented by 2 mA current of tDCS on two sides of the anterior temporal region for 20 minutes. The other one (EG2) contains 15 participants as a Sham group was experienced by tDCS with a similar process for 10 sessions. The difference is that the device was turned off after they felt an initial burning sensation. Finally, anxiety and severity of stuttering were evaluated before and after treatment. Findings: Based on the results, there was a significant difference between the experimental and sham groups in the anxiety of the subjects (P < 0.05, F = 645/725). In addition, there was a significant difference in the intensity of stuttering between the experimental and sham groups among participants (P < 0.05, F = 16.875).Conclusion: According to the results, compared to the Sham group, anxiety and the severity stuttering in stammering adolescents who were affected by tDCS, were reduced significantly. So, it seems that tDCS on both sides of the anterior temporal region can be effective in treating anxiety and severity of stuttering. Though, other similar studies in this field are needed to prove the obtained results.