The COVID-19 pandemic has represented a source of stress for teachers by adding new challenges. The objective of this study was to assess the association between emotion regulation and coping strategies, on the one hand, and perceived stress and affective experience on the other among teachers during the COVID-19 pandemic. A sample of 1178 of Italian pre-primary, primary, and secondary school teachers completed an online survey. Three hierarchical linear regression analyses were run to evaluate teachers' emotion regulation, coping strategies, years of teaching experience, perceived workload, and perceptions about online teaching in predicting their perceived stress and positive and negative affect. The findings showed that cognitive reappraisal and positive attitude were associated with a lower level of perceived stress and negative affect and a higher level of positive affect. Problem orientation strategies were also associated with a higher level of positive affect. By contrast, expressive suppression was correlated with a higher level of perceived stress. Avoidance coping strategies were associated with higher perceived stress and negative affect and a lower level of positive affect. The perceived burden of online teaching was positively related with perceived stress and negative affect. Confidence in using educational technologies predicted lower levels of perceived stress, and previous online teaching experience was positively correlated with positive affect. The findings of this study could be useful for implementing teacher training programmes on emotion regulation and coping strategies to reduce stress and promote positive affect.