The present study evaluated the psychometric properties of the Scale for Social Media- Induced Depression (SMID) in an Iranian sample, given rising rates of depression among adolescents and young adults alongside expanding social media engagement; using a descriptive correlational (psychometric) design, the SMID was administered to 550 participants aged 15–35 in Karaj (year 1404) recruited via convenience sampling, and confirmatory factor analysis (CFA) was conducted with LISREL 10.2 to compare competing measurement models and test the proposed three-factor structure (sensitivity and attention seeking, self-devaluation, and avoidance of reality); the CFA supported the three-factor model with satisfactory fit indices (RMSEA = 0.04, GFI = 0.95, NFI = 0.93, CFI = 0.95, SRMR = 0.05) and significant standardized loadings for items on their respective factors, internal consistency (Cronbach’s α) for the subscales ranged from 0.70 to 0.74 indicating acceptable reliability, and known-groups validity was examined via independent-samples t-test comparing participants with <5 hours versus ≥5 hours of daily social media use, those with ≥5 hours scored significantly higher on SMID (p < 0.05), providing convergent evidence for construct validity; limitations include the convenience sampling method, single-city data collection, reliance on self-report measures, and cross-sectional design, which restrict generalizability and preclude causal inference; nonetheless, findings suggest that the SMID is a reliable and valid instrument for assessing tendencies toward social media–related depressive symptoms in Iranian adolescents and young adults and may be useful for screening and evaluating intervention outcomes, while future research should address test–retest reliability, examine convergent and predictive validity with clinical measures, and replicate the validation in larger, more diverse and clinical samples to further establish the scale’s robustness and cross-cultural applicability.