International concern about youth suicide has led to a growing consensus that schools are a potentially important location for suicide prevention efforts. The present study investigated the experiences and perceptions of teachers regarding a role in youth suicide prevention through semi-structured interviews which were analysed using Interpretative Phenomenological Analysis. Three themes are reported which contribute to an understanding of the construction of teacher efficacy in relation to a role in suicide prevention: baseline mastery, threats to efficacy and tension between personal and professional identities. The results indicate a mix of positive and negative experiences relating to personal, process and systemic factors. Positive elements were associated with the pastoral role. Negative experiences related to referral pathways and broader systems of care. Implications for the development of school-based suicide prevention programmes and for conceptualising processes of change in school systems are discussed.