Background: As a result of national lockdown due to the COVID-19 outbreak, teachers were forced to suspend their classes and replace them with online teaching and home schooling. Additional stressors such as competing family responsibility have increased their worries and mental health problems. The aim of this study was to determine the impact of COVID-19-related worries on teachers' emotional symptoms, considering the mediating role of several protective factors. Methods: A total of 614 Chilean teachers (94.60% women) participated in this study using a cross-sectional design and incidental sampling method. Self-report data was collected assessing emotional symptoms, COVID-19-related worries, life satisfaction, affect balance, and resilience. Descriptive analyses, Pearson's correlations, hierarchical regressions, and mediation models were conducted. Results: The results indicated that emotional symptoms were associated with prepandemic physical and mental health problems, higher levels of worries and negative affect, as well as lower levels of life satisfaction and resilience. Results from the mediation models showed that the negative impact of COVID-19-related worries on emotional symptoms was alleviated by affect balance and resilience. Conclusions: These findings highlight the importance of addressing the risk and protective factors for teachers' mental health during exceptional situations such as the ongoing pandemic.