Introduction: The present study gives an account of the effects of Triple P, positive parenting program, on parenting styles as well as the attitude towards strengths and difficulties of the child.Methods: This study is a clinical trial, which sets out to explore the effects of psychiatric disorders on 30 parents – parents of teenagers being admitted to Imam Hossein Hospital, Tehran, Iran – based on the diagnosis of child psychiatrist, teenagers with psychiatric disorders were studied in two groups: trial and control. Positive parenting program i.e. Triple P sessions were held for the trial group while the control group received usual clinical services.Results: Based on the results of the present study, after holding 3P sessions, Baumrind’s parenting styles scores show some improvement in comparison with previous test scores; however, the difference was not statistically significant (p=0.167). The overall score of the child's strengths and difficulties questionnaire, that was completed by the parents, represents a statistically significant difference (p=0.02) between the test scores before and after the intervention.Conclusion: It is important to note that positive parenting interventions can improve and, at the same time, change parenting styles. Moreover, Triple P can change parents' attitudes concerning the strengths and difficulties of the child, not to mention improving their parenting styles. Our results are consistent with those of similar studies on children.