This qualitative study from Ontario, Canada, reveals that principal behaviors shape teacher emotions in important ways, influencing teacher morale, burnout, stress, commitment, and self- and collective efficacy. The findings suggest that principals can influence teacher emotions through several key behaviors: professional respect shown for teacher capability; providing appropriate acknowledgement for teacher commitment, competence, and sacrifice; protecting teachers from damaging experiences like harassment; maintaining a visible presence in the school; allowing teachers' voices to be heard; and communicating a satisfying vision for their school. Implications include greater awareness at the school and system level, as well as appropriate principal training.