The results of a substantial body of research affirm that the number of teachers leaving their jobs is on the increase and the evidence is strong that the most credible explanation for the attrition is the emotional nature of the profession. The present study aimed to explore the intervening effect of EFL teachers' anxiety on the correlations between their perfectionism and burnout levels. The participants were 276 Iranian EFL teachers. The data were analyzed by means of structural equation modeling. The findings revealed that, compared to other dimensions of burnout, depersonalization was more significantly affected by both direct and indirect effects of perfectionism. Moreover, the statistically insignificant direct associations between perfectionism and emotional exhaustion became significant due to the intervening impact of anxiety. The results of mediation analysis also confirmed the mediator role of anxiety. The results corroborate prior researches and offer illuminating insights into the mental health of teachers.