Today's teachers face intense stress (Robinson et al. in School Mental Health 15(1):78-89, 2023), which means they often need to regulate strong emotions, like frustration and anxiety, in the classroom. Given the importance of this skill for classroom life, it is essential that we gain a more nuanced understanding of teachers' emotion regulation (ER). The teacher ER literature is growing, and we aim to contribute meaningfully in three ways. First, we examine two general ER strategies (cognitive reappraisal and expressive suppression) descriptively in a sample of 190 public school teachers (grades K-6) from 33 elementary schools. Second, we explore whether these two ER strategies are correlated with important teacher (burnout, years of experience) and classroom (class size) factors. Third, we examine whether these ER strategies are linked to observed emotionally supportive classroom interactions. Teachers in this sample reported frequent use of cognitive reappraisal and relatively infrequent use of expressive suppression in general. These two ER strategies were not significantly correlated with one another. Teachers reporting greater use of cognitive reappraisal reported less burnout, while teachers reporting greater use of expressive suppression reported more burnout. Teachers with more years of experience also reported greater use of cognitive reappraisal. Contrary to our hypotheses, cognitive reappraisal and expressive suppression were not related to class size and did not predict unique variance in observed emotionally supportive interactions. Implications for teacher supports and interventions are discussed.