Highly effective principals are critical to their school systems, contributing to both student outcomes and teacher retention. But despite some stabilization during the pandemic, teacher and principal turnover rates are rising again at the district and school levels, especially at high-need schools. And our recent original research underscores an overlooked cyclical effect impacting teachers and students alike: When principals leave their schools, teachers are more likely to leave, as well. But when principals get effective support from their district office--including around attracting and retaining highly effective teachers--they're less likely to leave their school, which can stabilize teacher turnover rates and improve student outcomes and experiences. Our latest brief outlines four key supports that district leaders can provide to principals, mitigating the turnover cycle and boosting both principal and teacher retention.