Shahroud University of Medical siences Shahroud Journal of Medical Sciences 2423-6594 Exploring Irrational Beliefs Related to Happiness Among Adolescent Girls: A Qualitative Study eng Sara Ali Qanavati PhD student in Educational Psychology, Deprtment of psychology,Shk.C.,islami Azad university, Shahrekord,Iran. sara.ghanavati2112@iau.ir Reza Ahmadi Deprtment of psychology,Shk.C.,islami Azad university, Shahrekord ,Iran. Reza.ahmadi@iau.ac.ir Ahmad Ghazanfari Deprtment of psychology,Shk.C.,islami Azad university, Shahrekord,Iran. aghazan5@yahoo.com 2025 07 06 2025 12 13 Background: This study was conducted to identify and analyze irrational beliefs related to happiness among Iranian adolescent girls. Methods: This qualitative study employed a thematic analysis approach. Data were collected through the review of two domestic and nine international documents, as well as unstructured interviews with 13 adolescent girls in Ahvaz during the 2023–2024 academic year. Sampling was conducted in two stages: an initial screening using Yıldırım’s (2019) Irrational Happiness Beliefs Scale (IHBS), followed by purposive sampling until data saturation was reached. The interviews were conducted over a six-month period and analyzed using Braun and Clarke’s thematic analysis framework. Data credibility was ensured through peer checking and participant feedback. Results: The analysis resulted in the identification of seven main categories and seven subcategories: fear of happiness, fragile happiness (including transience and the perception of happiness as an immature emotion), external sources of happiness, essentialist views of happiness, perfectionistic expectations (from self, others, and life), contingencies of self-worth (based on others and achievement), and attention to the present moment (including rumination on the past and experiential avoidance). Conclusion: The findings of this study, by identifying seven main categories of irrational beliefs related to happiness among Iranian adolescent girls, offer deeper insight into the impact of cultural and gender factors on their psychological well-being. We recommend that school counselors and clinical psychologists implement individual and group interventions, along with mindfulness workshops, to address beliefs such as fear of happiness and perfectionistic expectations, thereby promoting mental health and sustainable happiness in this population.