Training Gatekeepers is a major component of mental health promotion and suicide prevention efforts around the world, training laypersons to identify, respond to and refer to people with mental health crises. In Hong Kong, where adolescent mental health problems have increased significantly in recent years, gatekeeper training programs have been systematically implemented in educational, community and workplace settings. The article reviews the gatekeeper training initiatives for mental health in Hong Kong comprehensively in terms of theory, program design, implementation strategies and evidence base. The review also covers the Education Bureau’s Peer Power – Student Gatekeeper Training Program, S.H.I.E.L.D.S. (Suicide Help Intervention through Education and Leadership Development for Students) program, QPR (Question, Persuade, Refer) Gatekeeper Training, parent gatekeeper workshops, and emerging community-based programs like the “Emotional Health Pioneer” international gatekeeper training. This article discusses some of the strengths and drawbacks of current Hong Kong programs, such as the difficulty of maintaining skills over the long term, the need for rigorous measurement of outcomes and the importance of cultural adaptation, using available evaluation data and international research on the effectiveness of gatekeeper training. The article concludes with suggestions for strengthening gatekeeper training as a sustainable component of Hong Kong’s evolving mental health infrastructure, emphasising the significance of embedding it within stepped-care models, developing better evaluation frameworks, and extending its reach to underserved populations.