Objective: To examine whether sexual assault prospectively predicts unhealthy weight management behaviors in college women. Method: Participants were female college students (N = 483) with monthly assessments across the first year, including the frequency and severity of sexual assault and unhealthy weight management behaviors. Results: Frequency of sexual assault prior to college predicted dieting, purging, and diet pill use, over the first year. Severity of those experiences predicted dieting and diet pill use. Frequency of sexual assault during the first semester predicted purging and diet pill use during the second semester. Severity predicted all three unhealthy weight management behaviors. Findings held consistently when controlling for socioeconomic status (SES), race/ethnicity, body mass index (BMI), and pre-college mood, anxiety, and eating disorders, as well as unhealthy weight management behaviors during the first semester in longitudinal analyses. Reverse models were non-significant. Conclusions: This research documents the detrimental effects of sexual assault on unhealthy weight management behaviors in college women, and highlights the importance of prevention and intervention.