Given the cost of treating eating disorders (EDs) and the substantial morbidity and mortality associated with these disorders, prevention of EDs has considerable public health significance. Research supports the use of a Healthy Weight (HW) program targeting small lifestyle modifications in the prevention of ED onset and in the reduction of ED risk factors. Studies show that HW can be tailored for specific social systems (e.g., sororities) which can facilitate dissemination and that undergraduate peer-leaders can implement these programs. Interventions that can be administered affordably by endogenous providers are more likely to be disseminated, as indicated by the large scale dissemination of a peer-led ED prevention program by a national sorority. Another target social system for dissemination of ED prevention is collegiate athletics. Research suggests that disordered eating among female athletes is prevalent, and that this group is often at greater risk for developing EDs than non-athlete females. Disordered eating is especially dangerous in female athletes because it increases risk for the Female Athlete Triad (i.e., low energy availability/disordered eating, menstrual disorders, and decreased bone mineral density/osteoporosis) and subsequent injury. Moreover, the triad puts athletes at risk for serious long-term health consequences, such as osteoporosis, reproductive disorders, and cardiovascular disease. Despite this, efforts aimed at prevention of EDs among this group remain surprisingly limited. A pilot study with female athletes suggests that a modified version of HW can be successfully implemented by peer-leaders within the constraints of a competitive athletics program with positive effects at 12- month follow-up. The proposed study is a randomized controlled trial of the HW intervention among female athletes. 500 female collegiate athletes from three sites will be randomized to either the HW prevention program or a brochure waitlist control condition utilizing group (cluster) randomization. Participants will complete surveys and telephone interviews at pretest, posttest, and at 6, 12, and 18- month follow-ups. We will examine; (1) the efficacy of HW in reducing empirically supported ED risk factors relative to a waitlist brochure control condition at 18 months, (2) whether HW impacts secondary outcomes, including knowledge and identification of the female athlete triad, treatment seeking for the triad, affect, and health care utilization, and (3) the underlying mechanisms (mediators) of the HW intervention effects.