Objective: To investigate the quality of randomized controlled trials (RCTs) of eating disorder prevention. Method: A systematic literature search was conducted in Medline, PsycINFO, Embase, Scopus, and the Cochrane Collaboration Library to January 2016. Studies were included if they were RCTs that tested an eating disorder prevention program. We identified 96 studies with a total 15,350 participants (91% female, M age = 17 years) and rated quality with the Quality Rating Scale (QRS; Moncrieff et al., 2001). Results: The mean QRS score was 62% (SD = 13%). Several standards of quality were not frequently fulfilled (i.e., failed to achieve an optimal rating), for example, power calculation (85%), intent-to-treat analysis (54%), blinding of assessor (75%), representative sample (78%), adequate sample size (75%), and appropriate duration of trial including follow-up (67%). QRS was positively and significantly associated with publication year, number of authors, and PubMed-indexation. Discussion: Given the majority of eating disorder prevention studies had problems with trial quality, it is recommended that future RCTs follow quality checklists and CONSORT guidelines, that RCTs are registered, and protocols published in advance. In addition, funding bodies are called on to deliver the support needed to ensure that preventions for eating disorders are efficiently and cost-effectively achieved.