The goal of the present study was to evaluate the effectiveness of a selective prevention program designed to reduce pressures to be thin in sport, and to promote positive body image and eating behaviors in young female athletes. Participants were competitive female gymnasts (aged 11 to 18 years), parents, and coaches from 7 gymnastic clubs across Ontario, Canada. Four of the seven clubs were randomized to receive the 3-month intervention program (IG) aimed at increasing awareness and positive climate change of body image pressures for athletes in their clubs. Three clubs were randomized to the control group (CG). A total of 62 female gymnasts (IG n = 31; CG n = 31) completed self-report questionnaires examining perceptions of pressure to be thin within their sports clubs, self-efficacy over dieting pressures, awareness and internalization of societal pressure to be thin, body esteem, and eating attitudes and behaviours before and following the intervention. A total of 32 mothers (IG n = 24; CG n = 8) completed measures examining their perceptions of their daughter's pressure to be thin, awareness and internalization of societal pressures to be thin, daughter's self-efficacy over dieting pressures, in addition to mothers' beliefs regarding thinness and success for women in society, before and following the intervention. The findings revealed that participation in the BodySense program resulted in athletes perceiving a reduction in pressure from their sports clubs to be thin, though no changes were found in body esteem, the EAT, or the SATAQ. No significant change was observed over time on mothers' measures. The role of climate change for prevention of eating disorders in athletes is discussed.