Introduction: generalized Anxiety affects patients' personal, social and occupational life Anxiety. according to this the present study was to investigate the effectiveness metacognition therapy on the Anxiety and psychological wellbeing of the patients with generalized Anxiety. Materials and Methods: The research method was quasi-experimental with pretest-posttest, control group design and two-month follow-up period. The statistical population of the current study was all the patients with social Anxiety referring to consultation centers in the city of Tehran in 2017. Nonprobable available and random replacement were used in the present study. After selecting the sample size and replacing them in the experimental and control groups, the experimental group received ninety-minute teaching interventions during three months once a week. The applied questionnaires in the current study included generalized Anxiety disorder (Spitner, et. al, 2006), Anxiety questionnaire (Beck, Epstein, Brown and Steer, 1988), psychological wellbeing questionnaire (Ryff, 1980). The data from the study were analyzed through repeated measurement ANOVA. Results: The results of data analysis showed that metacognition therapy have been effective on the Anxiety and psychological wellbeing of the patients with generalized Anxiety (P<0. 001). This treatment has been shown to reduce Anxiety and improve the psychological well-being of patients with generalized Anxiety disorder. Conclusion: According to the findings of this study, it can be concluded that metacognitive therapy is an effective way to reduce Anxiety and improve the psychological well-being of patients with generalized Anxiety disorder and can be used for patients with generalized Anxiety disorder.