ObjectivesSuicide prevention gatekeeper training (GKT) is considered an important component of an overall suicide-prevention strategy. The primary aim of this study was to conduct the first robust review of systematic reviews of GKT to examine the overall effectiveness of GKT on knowledge, self-efficacy, attitudes, behavioral intentions, and behavioral change. The study also examined the extent to which outcomes were retained long term, the frequency of refresher sessions, and the effectiveness of GKT with Indigenous populations and e-learning delivery.MethodsFor this review of reviews, MEDLINE, PsycINFO, Embase; and the Cochrane Database of Systematic Reviews were searched. ROBIS was applied to assess risk of bias and findings were synthesized using narrative synthesis.ResultsSix systematic reviews were included comprising 61 studies, of which only 10 were randomized controlled trials (RCTs). Immediate positive effects of GKT on knowledge, skills, and self-efficacy were confirmed, including for interventions tailored for Indigenous communities. Evidence was mixed for change in attitude; few studies measured e-learning GKT, retention of outcomes, booster sessions, behavioral intentions, and behavioral change, with some positive results.ConclusionsEvidence supports the immediate effects of GKT but highlights a need for more high-quality RCTs, particularly for Indigenous and e-learning GKT. This review identified a concerning lack of long-term follow-up assessments at multiple time points, which could capture behavioral change and a significant gap in studies focused on post-training interventions that maintain GKT effects over time. This first review of systematic reviews for GKT confirmed positive effects for GKT, although mixed evidence exists for changes in attitude.Very few studies include long-term measurement of retention of outcomes and what facilitates retention.There is an urgent need for more research into the effectiveness of GKT with Indigenous populations and e-learning GKT.