Hamadan University of Medical Sciences Journal of Education and Community Health 2820-896X 12 2 2025 06 30 Can a Positive Activity Intervention Based on a Mobile Application Improve Well-Being? 110 121 10.34172/jech.4732 EN Majid Barati https://orcid.org/0000-0002-5152-1928 Hanieh Jormand https://orcid.org/0000-0002-4582-1473 Babak Moeini Saeid Bashirian https://orcid.org/0000-0003-2133-087X Amir Keshavarzi Salman Khazaei https://orcid.org/0000-0001-5918-2310 Negin Ahmadvand Journal Article 10.34172/jech.4732 2025 03 26 2025 06 09 Background: Positive psychology emphasizes the importance of mental well-being. This study evaluated the effectiveness of a mobile application-based positive psychology intervention (PPI) in improving the well-being of university students in Hamadan, Iran. Methods: Using a multistage, cluster-randomized approach, this experimental study was conducted on 251 students from two universities in Hamadan, west of Iran, in 2021. The intervention consisted of fourteen educational courses delivered via a mobile app. Flourishing, depressive symptoms, and fear of COVID-19 were measured three months post-intervention. The obtained data were analyzed using SPSS-23 with chi-squared tests, independent samples t-tests, and IBM AMOS-26 software (P<0.05). Results: At the initial assessment, there were no notable discrepancies between the educational and comparison groups in flourishing, positive affect, hope, need satisfaction, and person-activity fit. However, three months after the intervention, the academic group demonstrated significant improvements in the aforementioned variables, except for depressive symptoms and fear of COVID-19, which decreased significantly. Thus, 34% of the variance of flourishing, a 0.05% decrease in depression, and 28% fear of COVID-19 can be explained based on the PPI. In other words, PPI had more effects on flourishing, fear of COVID-19, and depressive symptoms, respectively. Conclusion: The mobile app-based PPI could noticeably improve well-being indicators in the experimental group. Given the importance of enhancing happiness and well-being while reducing depression among the students, these findings underscore the need for serious actions, updated educational plans focused on well-being, and strategies to decrease health anxiety.