<p>Emotion regulation is crucial in teachers’ daily functioning, yet not all teachers can effectively manage emotions in every context. Exploring and comparing the adaptive and maladaptive emotion regulation of teachers may help delve into the nuances and challenges of teacher’s daily work. This qualitative case study involved 12 teachers in Chinese schools, using thematic analysis to identify teachers’ specific strategy use in their adaptive and maladaptive emotion regulation at work. Two themes, adaptive and maladaptive teacher emotion regulation, each containing four specific strategies were generated from the data. Notably, three strategies were reported with both adaptive and maladaptive use, depending on how they were implemented in what context and for what goal. This finding differs from most of the research that identified a particular strategy as adaptive/maladaptive (e.g., suppression as maladaptive strategy) and reveals the complexity of the relationship between teachers' emotion regulation strategies and adaptiveness.</p>