Background <p>Research indicates that elevated intolerance of uncertainty (IU) is cross-sectionally associated with eating disorder (ED) pathology in women. Although longitudinal data is needed to better understand whether IU is a prospective risk factor for EDs in the general population, IU also influences the performance of athletes, a population at risk for EDs. Despite the relevance of both IU and ED within athletics, research assessing the association of IU and ED pathology in athletes has yet to be conducted. The current study longitudinally explored IU as a potential modifiable risk factor for ED pathology in a sample of women athletes.</p> Methods <p>IU at baseline was hypothesized to predict downstream ED pathology. Participants (<i>N</i> = 393) were women athletes aged 18–39 years from athletic teams/activities across the United States who responded to surveys at baseline and at least one follow-up assessment (3-, 6-, and/or 12-months) as part of a large multi-measure longitudinal study of women athletes. IU and ED pathology were measured using the two-factor, 12-item Intolerance of Uncertainty Scale (IUS-12) and the nine-item Brief Eating Disorders in Athletes Questionnaire (BEDA-Q), respectively. Age-adjusted modified Poisson regression generalized estimating equations (GEEs) examined baseline IUS subscale scores as predictors of subsequent changes in prevalence of a probable ED.</p> Results <p>The prevalence of a probable ED in this sample was 22.7% at baseline. ED outcomes were significantly predicted by baseline scores of the prospective anxiety subscale of the IUS-12 but not the inhibitory anxiety subscale. A one-standard-deviation higher baseline score on the prospective anxiety subscale was associated with an 18% increase in prevalence of a probable ED over the course of the longitudinal study (<i>p</i> = .01).</p> Conclusions <p>Based on these findings, desire for predictability is a potentially modifiable target in preventing ED in women athletes.</p>