Objective: The responsibility of implementing nonsuicidal self-injury (NSSI) policy falls largely on school principals, yet few have received training regarding adolescent NSSI. Understanding principals' perceptions and roles in responding to NSSI among their students is essential to determining how best to address and reduce NSSI within school settings. Method: Principals and deputy principals (n = 63) completed self-report questionnaires. Interviews were also conducted with 24 respondents. Results: Most principals were involved in the response to student reports of NSSI; however, few had received any training on appropriate responses to NSSI. Barriers to responding effectively were a lack of training as well as resources in the community and school. Conclusion: Schools may benefit from more extensive and direct training about appropriately addressing and responding to NSSI within the school setting and an NSSI-specific policy with clearly outlined roles for principals and other school staff.