Background: Attention deficit/hyperactivity disorder is a kind of disorder that may lead to interpersonal, emotional, educational and domestic problems. Moreover, it may lead to high-risk behaviors among teenagers and this area of research is now a focus of attention for many researchers in order to find solution for its treatment and prevention. Objectives: The aim of present study was to determine the effectiveness of dialectical behavior therapy on the decrease of high risk behaviors among students suffering from attention deficit/hyperactivity disorder. Methods: This research was done experimentally and through designing pre-test and post-test and using control group. Research population included all male third-grade high school students suffering from attention deficit/hyperactivity disorder (case study: Ardabil city, 2015). Research sample included 40 male students suffering from attention deficit/hyperactivity disorder who were selected through multi-step cluster sampling and classified into two groups: experimental group (n = 20 subjects) and control group (n = 20 subjects). For data collection we used Iranian teenage risk-taking scale, Conner’s Adult ADHD Rating Scale- Self report form and Subscale and diagnostic interview based on DSM-5. The data were analyzed by univariate analysis of covariance (ANCOVA) model in the SPSS software version 22. Results: The results of univariate analysis of covariance showed that dialectical behavior therapy had been effective in decreasing high-risk behaviors (P < 0/001). The data analysis had showed that there was a significant difference between high-risk behaviors of control and experiment groups in the post-test. Conclusions: According to the findings training dialectical behavior is effective in controlling emotional behavior and in regulation of emotions; therefore, along with other therapeutic methods we can use this approach as an effective way to decrease psychological and behavioral problems mainly high risk behaviors of teenagers suffering from attention deficit/hyperactivity disorder.