Summary: Suicide is a major tragedy that touches many in the military, Veteran (former military), and public safety personnel (M/V/PSP) communities. One of the challenges in suicide prevention is developing whole-of-community engagement in suicide prevention, meaning finding opportunities for all elements of the public and private sectors, communities, and families to participate. The Canadian Institute for Military and Veteran Health Research hosted a by-invitation round table in Ottawa on May 23, 2018 to advance whole-of-community participation in suicide prevention for these three important populations. The Canadian Institute for Military and Veteran Health Research (CIMVHR) is ideally placed to assist in engaging the whole community in suicide prevention for military personnel, Veterans, and public safety personnel. On May 23, 2018, CIMVHR hosted a round table in Ottawa to begin the process of bringing together academia, military personnel, Veterans, public safety personnel, their families, and the public and private sector organizations. The event was planned as a pilot, since there was no precedent in the Canadian M/V/PSP communities for the complex process of whole-of-community engagement. The institute invited academia, Veterans, families, public safety personnel, non-governmental organizations (NGOs) and government service providers, including the Canadian Armed Forces and Veterans Affairs Canada. Chatham House rules were instituted to provide a secure atmosphere and to encourage participation. The goal of the round table was to prevent suicides in Canadian military personnel, Veterans, and public safety personnel. The objectives were to; start a discussion on suicide prevention in military personnel, Veterans, and public safety personnel; share suicide prevention knowledge and practices; start developing a “whole of community” approach that all stakeholders can take part in; and explore next steps. Six subject matter experts gave presentations summarizing the evidence base and frameworks for suicide prevention in serving military personnel, Veterans, and public safety personnel. Two Veterans provided valuable perspectives on suicide and suicide prevention from their lived experience and peer support work, including the Mental Health and Suicide Awareness program developed and run by the Princess Patricia’s Canadian Light Infantry Association. The subject matter experts clarified that while evidence is lacking in many areas of suicide and suicide prevention, much has been learned that can be put to practical use. Evidence-based frameworks have been developed for suicide prevention in the military and Veteran communities, and work is underway to build them for public safety personnel. Considerable advances have been made by researchers in understanding the epidemiology of suicidality in all three populations and exciting new research is underway. Outcomes of the rich round table discussions were condensed into seven themes, which outline opportunities and challenges for developing whole-of-community engagement in suicide prevention; provide education, training, and information for practitioners, improve support for transitions across the life course, provide support for identity challenges across transitions, promote whole-of-community communication, collaboration, and knowledge sharing, explore policy considerations for suicide prevention, evolve whole-of-community approaches to care for the suicidal person and reduce barriers to services. Participants wanted more information in several areas, and reported that the meeting was valuable and asked that further work be done in whole-of-community engagement.