The purpose of this study was to explore how returning to teaching during the Coronavirus disease (COVID-19) pandemic impacted teachers' stress and anxiety. Specifically, the study investigated how teachers' anxiety changed during the first month of school. Additionally, the study explored the association of teachers' stress and anxiety and predictor variables for changes in teacher anxiety while teaching during the COVID-19 pandemic. The present study included 329 elementary teachers from across the United States who completed a survey during the first week of October 2020. The results found that most teachers saw no change or an increase in anxiety during the first month. Significant predictors of increased teacher anxiety included stress and communication within the school, with virtual instruction teachers having the most increase in anxiety. In comparison, the no change in anxiety group included significant predictors of stress, virtual instruction, and communication within the school. The present study provides applicable information to schools and districts as there is limited empirical research on the impact of the COVID-19 pandemic on teachers. Teachers are working as frontline workers during the pandemic; thus, schools and districts need to monitor teacher stress and anxiety during the COVID-19 pandemic and provide the necessary support.