The COVID-19 pandemic resulted in unprecedented system-wide school closures around the world. In NSW, where this study was conducted, ‘non-essential’ workers were required to stay home and keep their children home from school where possible, for a period of approximately eight weeks from March 2020. In response, teachers rapidly developed approaches for students to engage in ‘learning from home’, moving to online modes of teaching in a matter of days, with limited external support. This disruption to normal school practices resulted in an exponential increase in teachers’ workloads and has raised concerns for their wellbeing. In this paper, we draw on rigorous empirical evidence to shed light on what it was like to teach in 2020 during the COVID-19 pandemic in NSW.Enabled by our position of being in the middle of conducting a randomised controlled trial (RCT) when COVID-19 struck, we compare quantitative indicators of self-efficacy, morale, and sense of appraisal and recognition for a cohort of teachers affected by the pandemic (data collected in 2020) with a similar cohort of teachers unaffected by the pandemic (data collected in 2019). Analysis of survey data (n = 362) demonstrated that teachers’ morale and belief in their capacity to engage students declined significantly during COVID-19. In addition, we analysed teachers’ accounts of the effects of the pandemic on their lives, using interviews with teachers and school leaders (n = 18) conducted during 2020.We found that, despite working incredibly hard for their students, teachers felt dispensable and unappreciated, evidenced by flagging morale and declining self-efficacy. Teachers and school leaders reported increased workload and emotional exhaustion, conditions that can lead to a stronger desire to leave the profession. Such attrition could be devastating for Australia at a time when teacher shortages are predicted to increase. Despite reporting poorer behaviour by students after the learning from home period, there were no differences between the two cohorts in their efficacy for classroom management. However, in 2020, teachers reported lower efficacy in engaging their students in learning. These results signal that teacher wellbeing is at a critical juncture, with additional support for teachers required as the pandemic continues and beyond.