The present study aimed to examine the psychometric properties of the Teacher Emotion Regulation Scale (TERS) in a sample of Iranian teachers. This questionnaire includes five core emotion regulation strategies: avoidance, cognitive reappraisal, suppression, active modification, and tension reduction, each representing different ways in which teachers manage their emotions in the educational environment. Considering the importance of emotion regulation in the quality of educational interactions, professional performance, and teachers’ mental health, it was essential to investigate the validity and reliability of this tool within the Iranian cultural context. The study population consisted of all secondary school teachers in Tehran during the 2023–2024 academic year, from which a sample of 350 teachers was selected using multistage cluster sampling. Various statistical methods were employed for data analysis, including exploratory and confirmatory factor analyses to examine the factor structure, Cronbach’s alpha to estimate reliability, and convergent validity indices. The findings indicated that the Persian version of the TERS, like the original version, demonstrated a five-factor structure, with all strategies identified with appropriate factor loadings. The reliability coefficients of the subscales ranged from 0.85 to 0.90, indicating satisfactory internal consistency. Furthermore, evidence of convergent validity confirmed significant associations between the questionnaire dimensions and related constructs. Based on these results, the Persian version of the TERS can be considered a valid and reliable tool for assessing emotion regulation among Iranian teachers and can be utilized in future research as well as in intervention and educational programs.