The practice of educating individuals (known as ‘gatekeepers’ [GK]) at the informal social level with the knowledge, skills, and confidence to identify an at-risk individual and provide support has been shown as an effective suicide prevention method. Despite the efficacy of gatekeeper training (GKT) in the short-term, there are concerns over the long-term efficacy of these outcomes. The objective of this review was to identify the empirical GKT studies in the literature that included evaluations at pre, post, and follow-up. Additionally, this review aimed to evaluate the long-term effect of training on GK behavior. PubMed, Cochrane Library, and PsycNET databases were searched using the terms ‘gatekeeper’ and ‘suicid*’ present in the title and/or the abstract, with the terms ‘follow-up’, ‘pre-post’, or ‘long-term’ present in any text. Studies must have involved a suicide prevention program intervention provided to general members of the community. Knowledge and self-efficacy were shown to exhibit the strongest endurance of training effect, although some decay was present for knowledge over time (M follow-up delay 6.1 months). Gatekeeper attitude at follow-up (M follow-up delay 4.4 months) had returned to baseline levels in 57% (4/7) of the identified studies that evaluated this construct. Behavioral intention and behavior both indicate a weak training effect with poor translation of training into intervention behavior. Findings indicate the ideological and socio-cultural aspects of individual GKs should also be addressed to facilitate the improved potential for long-term attitudinal change. Future research directions are discussed.