Schools are becoming more stressful work environments, and teachers are becoming more vulnerable to job-related stress because of innovation overload, high job demands, and work-family conflict (WFC). Enhancing teachers' psychological capacities may prove helpful in managing stress under such work conditions. While past research has focused on the relationship between WFC and stress, there is limited empirical evidence in the education context on the effect of psychological capital (PsyCap) on changing the magnitude of (moderating) the interplays between WFC and stress. Therefore, this study investigates the moderation effect of teachers' positive PsyCap on the relationship between teachers' WFC and job stress. We adopted a quantitative research method and collected data from a randomly selected sample of 385 teachers in Siirt, a city in the South-East region of Turkey. Data were analyzed through descriptive, correlation, and hierarchical moderated regression statistics. Results indicated that WFC increases teachers' job stress, and PsyCap moderates the relationship between WFC and job stress by mitigating the effects of WFC on teachers' job stress.