Background: Past research has yielded promising results on the effectiveness of Internet-based interventions to prevent eating disorders (EDs) in adolescents, but further information is needed to evaluate the public health impact of their large-scale dissemination. This article used an established framework to systematically review the extent to which indicators of the reach, effectiveness, adoption, implementation and maintenance [cf. Reach-Effectiveness-Adoption-Implementation-Maintenance (RE-AIM)-framework] of universal and targeted online ED prevention programmes are reported in the literature, in order to estimate their future dissemination potential. Methods: The literature search was conducted on PubMed, Web of Science and PsycINFO, and complemented by searching existing reviews and the reference lists of the studies included. Twenty-two studies published between 2000 and April 2019 met the inclusion criteria. We extracted data on a total of 43 indicators, within RE-AIM dimensions for each article, including qualitative coding of fostering and hindering factors. Results: Reach (55.0%) and implementation (54.0%) were the dimensions reported on most frequently, followed by effectiveness (46.8%), adoption (34.7%) and maintenance (18.2%). While internal validity indicators were frequently reported (e.g. sample size, effects and intervention intensity), most studies failed to report on elements of external validity, such as representativeness of participants and settings, adoption rates, implementation costs and programme sustainability. Conclusions: Evidence indicates that Internet-based ED prevention programmes can reach a large number of adolescents and can be feasibly implemented in school settings. However, given the paucity of large-scale dissemination studies available for review, the degree to which schools are willing to adopt preventive interventions, as well as the transferability of programmes to different settings and geographical regions remains unclear.