The present study was conducted to compare the effectiveness of mindfulness-based therapy and narrative therapy on the positive youth development in the adolescents with anxiety disorder. It was a quasi-experimental study with pretest, posttest and control group design. The statistical population of the present study included 12-to-15-year-old adolecsents with anxiety disorder who referred to Avin, Roshd and Manooshan consultation centers in the city of Tehran in the spring and summer of 2021. 38 adolescents with anxiety disorder were selected through purposive sampling method and randomly accommodated into experimental and control groups. The experimental group separately received ten sessions of mindfulness-based therapy and narrative therapy in two-and-a-half months. The applied questionnaire in this study included positive youth development (Geldhof, et.al, 2014) and the questionnaire of children and adolescence anxiety (Spence, 2007). The data were analyzed through ANCOVA method and LSD post hoc test. The results showed that narrative therapy and mindfulness based therapy have had significant effect on the anxiety and positive youth development in the adolescents with anxiety disorder (p<0.01) while no significant difference was observed between the degree of the effectiveness of these therapies (p≤0.05).