Language teacher immunity has recently attracted the attention of the scholars interested in teacher psychology. Following the previous line of research in teacher psychology, the present study explored the immunity types among 260 Iranian EFL teachers working in schools and language institutes. Drawing on Hiver’s (2017) categorization, this study found that the participants were classified into productively and maladaptively immunized teachers through cluster analysis. It was also found that gender played a significant role, and female participants were more productively immunized than men. Regarding the role of teaching experience, it was found that EFL teachers’ immunity fluctuated in the late stages of their practice to a more fossilized, negative one. Regarding age differences, the results also suggested different immunity types among the participants of different age groups. The results implied that teacher education programs should enhance EFL teachers’ understanding of language teacher immunity as an important factor in their effectiveness and well-being as well as students’ achievement.
