Educators and policymakers across the country have been raising alarms about a growing teacher shortage. In Michigan, teacher shortages were so severe in the 2018-19 school year that 2,500 classrooms were staffed by long-term substitutes--nearly ten times the number placed in classrooms five years prior. The COVID-19 pandemic has raised even greater concerns about the supply of teachers, with several surveys of Michigan educators administered early in the COVID-19 pandemic indicating that a substantial proportion of full-time and substitute teachers are considering leaving the teaching profession due to pandemic-related concerns. In this study, we use administrative data from Michigan to understand how teachers' propensities to leave the public school system, switch districts, or switch schools shifted after the onset of the COVID-19 pandemic.