Background <p>This study evaluated the psychometric properties of the Contextualized Emotion Regulation Survey for Adolescents (CERSA) in Iranian adolescents, examining its utility for assessing emotion-specific regulatory strategies and their associations with mental health outcomes.</p> Methods <p>We administered the Persian-translated CERSA to 1362 adolescents from grades 5–12 in Tehran. After screening, the final sample included 990 adolescents (69.6% female, M_age = 15.79). We tested competing measurement models, examined measurement invariance across demographic groups, and assessed convergent and criterion-related validity through correlations with established measures of emotion regulation, psychopathology, and functional impairment.</p> Results <p>Exploratory Structural Equation Modeling demonstrated superior fit across all three emotional contexts (Sadness, Fear, Anger), supporting the original seven-factor structure with well-defined factors (λ = 0.38–0.95) and satisfactory reliability (ω = 0.78–0.91). Full measurement invariance was found across sex and birth order. Females scored higher on Rumination across all emotions and on Reappraisal for sadness and fear. Third and later-born adolescents reported higher Rumination for sadness and anger and elevated Dysregulation for anger compared to both first- and second-born peers. The CERSA subscales yielded satisfactory convergent validity with established emotion regulation measures and meaningful criterion validity, with Dysregulation, Rumination, and Control showing the strongest associations with psychopathology and functional impairment.</p> Conclusions <p>Results support the utility of the CERSA scales as context-sensitive measures of emotion regulation in Iranian adolescents and suggest that emotion regulation is best conceptualized as a multidimensional construct comprising distinct but interrelated strategies and abilities that vary across emotional contexts.</p>