Background: Positive Psychology (PP) has been found in numerous studies to improve symptoms of depressive disorders in patients when provided as part of therapy. Aim of the study: to evaluate the effect of positive psychology interventions on psychological flourishing, optimism, and hope among depressive patients. Research Design: A quasi experimental design was carried out. Subjects: A purposive sample of 50 patients with depression was recruited in the pre-test as well as the same sample in the post-test. Setting: This study was conducted at the El Azazi Mental Health Hospital in Abo Hamad City, El Sharkia, Egypt. Tools of data collection: Five tools were employed in this study: Demographic sheet, Beck Depression Inventory-II Scale, Short Flourishing scale, Life Orientation Test-Revised (Optimism), and Adult Hope Scale Results: The study revealed that the proportions of studied patients' moderate and severe levels of depression decreased after the intervention, and there were highly statistically significant improvements in the post-intervention mean score of depression, psychological flourishing, optimism, and hope. There was a positive correlation that was statistically significant between patients' scores of hope and flourishing at pre-intervention. Moreover, psychological flourishing was highly positively statistically correlated with optimism, whereas, optimism was highly negatively statistically correlated with depression after intervention. Conclusion: The positive psychology intervention was successful in improving depressive symptoms, psychological flourishing, optimism, and hope among depressive patients. Recommendations: It is recommended future study must involve larger numbers of participants from varied populations, and broad examinations to follow up are required.