Objective: Body dissatisfaction elevates the risk for disordered eating behaviors. Excessive exercise is prevalent among college women and associated with harm. Risk theory posits a bidirectional relationship between risk factors for disordered eating behaviors and the behaviors themselves. This study investigated the longitudinal, reciprocal relationship between body dissatisfaction and excessive exercise. Participants and methods: College women (n = 302) assessed in August (baseline) and November (follow-up). Results: Baseline body dissatisfaction significantly predicted increases in excessive exercise endorsement at follow-up, controlling for baseline excessive exercise endorsement and body mass index (BMI). Baseline excessive exercise endorsement predicted increases in body dissatisfaction at follow-up, controlling for baseline body dissatisfaction and BMI. Conclusions: Findings support the presence of a positive feedback loop between body dissatisfaction and excessive exercise; both predict increases in risk for the other, regardless of weight status. Future research should test whether this process is ongoing and predicts further distress.