We estimate the effects of year-round school (YRS) calendars on teacher turnover and teacher qualifications for the state of California, finding that YRS results in diminished teacher education and experience. This result is notable as previous research finds negative academic impacts of YRS in California. As context for our findings, we use comparisons with North Carolina, where research has found neutral academic impacts for the same calendar. While we find that schools in both locations hire more teachers to accommodate the calendar, teacher qualifications do not decrease for North Carolina. Our results are therefore consistent with, and can partly explain, evidence on the impact of YRS on student achievement. Additionally, as YRS is implemented in more affluent areas in North Carolina and in disadvantaged populations in California, we use matched samples to show that student demographics do not explain our teacher impacts found for California.