This study aims to determine the fit of a structural model predicting social anxiety based on upward social comparison, with self-concept and rumination serving as mediating variables among young adults aged 20 to 35. The research design is descriptive-correlational using structural equation modeling (SEM). The target population consists of young adults aged 20–35 residing in Tehran during 2025–2026. A sample of 200 participants will be selected via convenience sampling. Data will be collected online using the Social Phobia Inventory (SPIN), the Social Media Social Comparison Scale (SMSCS), the Questionnaire of Self-Concept-18 (QSC-18), and the Ruminative Response Scale-22 (RRS-22). Data analysis will be performed using regression and SEM via SPSS and AMOS software.

All ethical principles will be strictly observed throughout the research process, including obtaining informed consent, ensuring voluntary participation, guaranteeing data confidentiality, maintaining participant anonymity, and respecting the right to withdraw at any stage. The findings of this study can contribute to a deeper understanding of the psychological mechanisms associated with social media use and aid in developing preventive interventions to enhance self-concept and reduce social anxiety among young adults.