Amid heightened concerns of teacher shortages, we document the role of principals in shaping teachers' labor market decisions. Using teacher transfer applications from a large urban school district, we find that teachers are most likely to seek transfer away from schools with less-experienced principals and weaker leadership. The qualities of principals that attract applicants are survey reports of strong leadership, applicant-principal demographic congruence, and especially having worked with the principal previously. Ultimately, schools with high rates of teacher transfer seeking and exit receive few applications per teacher vacancy. These schools are likely to have shallow applicant pools and may need district support with recruitment in the short term, with the longer-term goal of developing leaders who retain teachers.