Gambling disorder in youth is an emerging public health problem, with adolescents and young adults constituting a vulnerable age group for the development of gambling-related problems. Although research has been conducted on the risk factors for gambling disorder, very few rigorous studies can be found on the efficacy of preventive interventions in young people. The aim of this study was to provide best practice recommendations for the prevention of disordered gambling in adolescents and young adults. We reviewed and synthesized the results of existing RCTs and quasi-experimental studies covering nonpharmacological prevention programs for gambling disorder in young adults and adolescents. We applied the PRISMA 2020 statement and guidelines to identify 1483 studies, of which 32 were included in the systematic review. All studies targeted the educational setting, i.e., high school and university students. Most studies followed a universal prevention strategy, that particularly targeted adolescents, and an indicated prevention strategy for university students. The reviewed gambling prevention programs generally showed good results in terms of reducing the frequency and severity of gambling, and also regarding cognitive variables, such as misconceptions, fallacies, knowledge, and attitudes towards gambling. Finally, we highlight the need to develop more comprehensive prevention programs that incorporate rigorous methodological and assessment procedures before they are widely implemented and disseminated.