Objective: To assess the effectiveness of a peer-led single-session intervention targeting the sociocultural pressures of body image. Participants: New members of 13 sororities at one university. Methods: Participants were randomized by sorority into the intervention (n = 207) or wait list control (n = 264). Online surveys were administered at baseline and one month to assess social determinants of body image, body image dissatisfaction (BID), and body appreciation. Multiple logistic and linear regression analyses compared changes over time between groups. Results: We observed significant improvements in overall sociocultural pressures of body image (p = 0.001) and the subscales of Norms (p < 0.001) and Perceived Norms (p = 0.009) of eating and exercise behaviors. Change in BID and body appreciation did not differ between groups. Conclusion: A one-hour peer-led community-level intervention can lead to positive changes in sociocultural pressures in new initiates to a sorority.