Language teachers tolerated major challenges during the COVID-19 pandemic. In such stressful teaching environments, Language Teacher Immunity (LTI) was introduced to function as a protective armor. This study explored the potential contributions of teacher occupational stress, foreign language teaching enjoyment, and teaching experience to LTI formation in Iranian EFL teachers during the pandemic in terms of (1) their pairwise associations, (2) traces of difference in those associations, and (3) their predictive power. A total of 208 Iranian EFL teachers were non-randomly selected, grouped into the novice and the experienced, and surveyed with validated questionnaires. Multiple correlation analyses depicted a positive pairwise relationship between LTI, occupational stress, teaching experience, and teaching enjoyment; a negative pairwise relationship between occupational stress, teaching experience, and teaching enjoyment; and no significant relationship between teaching experience, and teaching enjoyment in both groups. Differences in the observed associations were statistically significant only for LTI/teaching experience, and LTI/occupational stress in both groups. Moreover, multiple regression analysis indicated that occupational stress and teaching enjoyment could explain 47.3% of the LTI variance in the experienced and only 14.9% in the novice teachers. Findings implied that the developed LTI in Iranian EFL teachers was productive and a consequence of the COVID-19 crisis.