This research attempted to determine the effect of positive psychotherapy anchored on Martin Seligman’s theory of Authentic Happiness (2002)as an intervention to adolescents’ depression. Specifically, the study intended to seek the respondent’s level of depression before the experiment; the respondent’s level of depression after the experiment; and the significant effect of positive psychotherapy on the respondent’s level of depression. Based on the results, the mean score of the levels of depression among the experimental subjects before the treatments was 25.15. After the 20 adolescents undergone in positive psychotherapy the computed mean decreased by 10.01 that made the mean posttest 15.05. This implies the significant change happened in the respondents’ depression after conducting the positive psychotherapy exercises. It is therefore concluded that the Positive Psychotherapy has a great effect in reducing the depression among the respondents. Further studies are highly recommended.