Aim: This study examined the mediating effect of occupational self-efficacy on the relationship between occupational stress and job-related affective well-being among teachers.Method: In this correlational study, statistical population included 284 teachers from Divandareh city in the 2012-2013 academic year. On a sample consisting of 250 teachers, who were selected through simple randomized sampling, were administrated the Occupational Stress Inventory- Revised (OSI-R, Osipow, 1998), Teacher Self-Efficacy Scale- Short Version (TSES-SV, Schwarzer, Schmitz & Daytner, 1999) and Job-Related Affective Well-Being Scale (JAWS, Van Katwyk, Fox, Specter & Kelloway, 2000). Structural equation modeling was used to assess the mediating effects model of occupational self-efficacy on the relationship between occupational stress and job-related affective well-being among teachers.Results: In hypothesized model, results indicated that there is a significant negative correlation between occupational stress with occupational self-efficacy and job-related affective well-being and significant positive correlation between occupational self-efficacy with job-related affective well-being. In this model, results also indicated that the relationship between occupational stress and job-related affective well-being by occupational self-efficacy is mediated. All of the regression weights in the model were statistically significant and model' predictors accounted for 64% of the variance in job-related affective well-being.Conclusion: These findings show that when encountering to occupational stress, difference in job-related affective well-being accounted for by difference in degree of occupational self-efficacy.