Problematic Internet use (PIU) can lead to dysfunction and undesired consequences, especially in adolescents and youths. Preventive interventions can reduce them, but should be built on sound evidence. This review synthesizes the available evidence on the effectiveness of primary prevention programs for PIU in adolescents and youths. It adds to previous reviews by broadening the search to general and specific problematic behavior. Two independent reviewers performed a systematic search for published studies on PIU and internet addiction in English, French and Spanish using PubMed, PsycINFO, Cochrane Register of Controlled Trials, and Scopus. Published experimental and quasi-experimental studies that assessed the effectiveness of primary prevention programs targeting PIU behaviors were considered for inclusion. Full texts for eligible studies were retrieved and assessed for quality. Five studies were retained for narrative synthesis. Three of them based the intervention strategy on an underlying theory, one on media literacy, and one used an educational-based approach. A meta-analysis showed that all five interventions were effective in preventing internet addiction separately. However, when using the Hartung-Knapp-Sidik-Jonkman (HKSJ) estimator and removing one of the studies because of a disproportionate Hedges’ g, combined effects were no longer significant. Although PIU is a popular topic, little is known about ways to prevent it. This review demonstrates that prevention programs can be based on different theoretical approaches, but that the available evidence is too heterogeneous to derive generalizable conclusions concerning their effectiveness.