BACKGROUND: The COVID-19 pandemic has had drastic effects on K-12 teachers. Researchers partnered with a teacher advisory board to identify factors associated with K-12 teachers' consideration of leaving teaching during Fall 2020. METHODS: A web-based survey focused on teachers' working experiences was emailed to school union membership listservs in Indiana, Kentucky, and Ohio. A logistic regression model was developed to identify working conditions associated with teachers considering leaving the profession. RESULTS: Among 5873 K-12 teachers, 27% (n = 1319) were considering leaving the profession either because of COVID-19 (10%), for other reasons (6%) or were undecided (11%). Teachers who were midcareer, having taught 6-10 years, who perceived less supervisor support, whose job duties had changed significantly, who were dissatisfied with the COVID-19 related decision-making, who reported poor or fair mental health, and who were mostly or extremely afraid that a household member would get COVID-19 had higher odds of considering leaving teaching or being undecided about future career plans. IMPLICATIONS FOR SCHOOL HEALTH POLICY, PRACTICE AND EQUITY: Understanding factors influencing teachers' career decisions will help school leaders improve teacher retention amid challenging circumstances. CONCLUSION: In this study in 3 midwestern US states, limited supervisor support, significant job duty change, dissatisfaction with COVID-19-related decision-making, poor or fair mental health, and fear that a household member would get COVID-19 were associated with teachers' consideration of leaving the profession or being undecided about future career plans.