Background and aims: Behavioral addictions are a public health problem that causes harm to both individuals and society. Internet-based interventions offer potential benefits over face-to-face therapy for the treatment of behavioral addictions, including their accessibility, perceived anonymity, and low costs. We systematically reviewed the characteristics and effectiveness of these interventions. Methods: A systematic literature search was conducted in: PubMed, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials. A standardized methodological quality assessment was performed on all identified studies via the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool. Results: Twenty-nine studies were assessed in this systematic review. Between them, considerable heterogeneity was noted in various study characteristics, including screening tools, inclusion criteria, and outcome measures. Attrition rates also ranged widely (9-89%), as did study quality, with three of the 29 studies rated strong, 12 moderate, and 14 weak methodologically. Twenty-two studies focused on gambling disorder, most revealing significant within-group effects for the assessed intervention on gambling-related symptoms and four of these studies identified significant between-group effects. Behavioral addictions studied in the remaining studies included gaming disorder, internet use disorder, hoarding disorder, and pornography use disorder, revealing generally-promising, albeit limited results. Conclusions: Internet-based interventions seem promising at reducing gambling problems, but too few studies have been published, to date, for conclusions to be drawn for other behavioral addictions. Internet-based interventions targeting other behavioral addictions - like gaming disorder, internet use disorder, hoarding disorder, and pornography use disorder - remain under-examined, warranting considerable additional research to assess their effectiveness. Kulcsszavak: behavioral addiction, impulse control disorders, internet-based interventions, effectiveness, systematic review