Background: The International Association for Suicide Prevention (IASP) and the World Health Organization (WHO) recommend that every country should adopt, or make progress towards the adoption of, an evidence-informed national suicide prevention strategy. Over the past four decades, more than 40 countries have adopted such a strategy, which typically promotes a coordinated and sustained multisectoral approach to suicide prevention, involving a range of governmental and non-governmental agencies working in collaboration, both locally and nationally. Although the case for national suicide prevention strategies has been persuasively argued and widely accepted, the impact on suicide rates (and other intended outcomes) which can be attributed to the implementation of national suicide prevention strategies as a whole has not yet been evaluated. We have conducted a systematic review to fill this knowledge gap. Methods: This review was informed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and used the Quality Appraisal for Diverse Studies (QuADS) tool to rate the quality of included primary studies. Twelve databases were searched for relevant literature published at any time in any language, complemented by searches for ‘grey literature’ from relevant government departments, research institutes and NGOs, conducted via the internet and contact with global experts. The contribution of national suicide prevention strategies, as implemented, to changes in population suicide incidence (and other intended suicide-related outcomes) was assessed in the first instance by means of narrative synthesis. The possibility of conducting a meta-analysis is being explored. Findings: A total of 9455 citations was generated from which 24 reviews in scope were identified. Preliminary analysis based on four key studies provides some support for the proposition that national strategies are associated with a reduction of suicide compared to the pre-implementation period, although findings thus far may reasonably be described as “promising” rather than “convincing.” In two studies, the decline in suicide was restricted to subgroups of the population (defined by age and sex), while in another two studies there was evidence of a decline in suicide in some, but not all, countries following the implementation of a national suicide prevention strategy. The definitive findings, based on the analysis of all eligible studies and including a meta-analysis (if feasible), will be reported at the conference. Conclusion: The extant incomplete or conflicting evidence may arise as a result of multiple factors, relating to both methodological and implementation limitations. Further evaluation of strategies with strong implementation measures, using methodologically robust evaluation designs, is urgently required.