Background: In their daily work life, teachers experience various situations in which they need to regulate their emotions. Possible factors that influence the use of different emotion regulation strategies include the emotions and context experienced. Previous research mainly investigated teachers' emotion regulation at a single strategy level without considering multiple strategies use, emotions, situational aspects and well-being. Aims: This study aimed to explore teachers' emotion regulation in their daily work life. Furthermore, we examined their emotions, specific situations and well-being linked to regulation behaviour. Sample: In total, 165 teachers (mean age 43.31 years; 83.6% female) participated in a diary study for two weeks. Methods: We assessed eight emotion regulation strategies, joy and anger, the valence and context of the situation and emotional exhaustion. The data were analysed using multilevel latent profile analyses. Results: We found different combinations of emotion regulation strategy use at the situational level (Level 1) and the person-level (Level 2). At the person-level, only a few teachers (17.4%) were able to flexibly apply different strategies in different situations, while most teachers regulated their emotions predominantly with a specific set of strategies. Experiencing joy, as well as the valence and the context of the situation, mattered for emotion regulation at the situational level. Emotional exhaustion at the person-level was not linked to profile probability. Conclusion: The findings highlight the complexity of teachers' emotion regulation, revealing diverse regulation patterns and profiles influenced by emotions and situational factors, while underscoring the limited flexibility in strategy use among most teachers.