Objectives. To assess the impact of state COVID-19 vaccine mandates for health care workers (HCWs) on health sector employment in the United States. Methods. Using monthly state-level employment data from the Quarterly Census of Employment and Wages between January and October 2021, we employed a partially pooled synthetic control method that accounted for staggered mandate adoption and heterogeneous treatment effects. We conducted analyses separately for the 4 health care subsectors-ambulatory health care services, hospitals, nursing and residential care, and social assistance-with an additional analysis of 2 industry groups-skilled nursing care and community care for the elderly-under the nursing and residential care subsector. We further explored possible heterogeneous impacts according to the test-out option availability. Results. Mandate impact estimates were statistically indistinguishable from zero. Results further ruled out a mandate-associated decrease in employment larger than 2.1% of premandate employment levels for the 6 health care domains examined and for states with no test-out option. Conclusions. State COVID-19 vaccine mandates for HCWs were not found to be associated with significant adverse impacts on health sector employment even in states without a testing alternative to vaccination. The findings support vaccine mandates as a viable preventive measure without material disruption to the health care workforce, including in times of public health emergencies. (Am J Public Health. 2025;115(3):344-348. https://doi.org/10.2105/AJPH.2024.307906).