Objectives: To investigate the effectiveness of Body Project groups delivered virtually (vBP) by peer educators for prevention of eating disorders. Method: In a randomized controlled trial vBP groups (N = 149) were compared with a placebo (expressive writing, EW: N = 148) over 24-month follow-up and to a waitlist control condition (N = 146) over 6-month follow-up among females (15-20 years old) with body image concerns. The primary outcome was incidence of eating disorder onset over 2-year follow-up measured by blinded diagnostic interviews. Waitlist participants were offered the vBP after 6 months. Results: The incidence of eating disorders onset over 24 months follow up were 3 in vBP (2.0%) and 13 in EW (8.8%), a significant difference; Hazard Ratio (Experiment B) = 0.26, 95% confidence interval (CI) [0.075, 0.92], p = .037. Incidence of eating disorder onset in vBP participants was 77% less than in EW participants. The vBP participants generally showed significantly greater reduction in eating disorder symptoms, clinical impairment, body dissatisfaction, and internalization of thin ideal compared with the waitlist participants at postintervention and 6-month follow-up, and in eating disorder symptoms, restraint, body dissatisfaction, and internalization of thin ideal compared with the EW participants at postintervention, and 6-, 12-, 18-, or 24-months follow-up. EW participants reported significantly greater reduction in clinical impairment and body dissatisfaction at postintervention compared with the waitlist participants. Conclusions: The present reduction in the incidence of eating disorders is notable given that the intervention was implemented virtually, rather than in-person. The vBP might be a viable option for future evaluation of scalable prevention of eating disorders.