Growing suspension rates predict major negative life outcomes, including adult incarceration and unemployment. Experiment 1 tested whether teachers (n = 39) could be encouraged to adopt an empathic rather than punitive mindset about discipline—to value students’ perspectives and sustain positive relationships while encouraging better behavior. Experiment 2 tested whether an empathic response to misbehavior would sustain students’ (n = 302) respect for teachers and motivation to behave well in class. These hypotheses were confirmed. Finally, a randomized field experiment tested a brief, online intervention to encourage teachers to adopt an empathic mindset about discipline. Evaluated at five middle schools in three districts (N_teachers = 31; N_students = 1,682), this intervention halved year-long student suspension rates from 9.6% to 4.8%. It also bolstered respect the most at-risk students, previously suspended students, perceived from teachers. Teachers’ mindsets about discipline directly affect the quality of teacher–student relationships and student suspensions and, moreover, can be changed through scalable intervention.