Abstract: While bulimia nervosa (BN) and binge eating disorder (BED) are prevalent in military populations, an understanding of risk and protective factors is limited by a lack of longitudinal population-based epidemiologic research. This study examined the prevalence of BN and BED among active-duty service members and identified military and psychosocial factors associated with their development. Millennium Cohort Study participants were followed for up to 15 years, and prevalence was ascertained using survey and electronic medical record data. Longitudinal multivariable logistic regression models evaluated risk factors associated with the development of BN (n = 96 245) or BED (n = 113 733). Weighted prevalence estimates from survey data (range, 0.80%-4.80%) were higher than those from medical records (0.04%-0.14%). Military factors significantly associated with increased risk for BN and BED included active-duty component (vs. Reserve/Guard); serving in the Army, Marine Corps, or Navy/Coast Guard (vs. Air Force); and combat deployment (vs. deployment without combat). Associated psychosocial factors included lack of social support, experiencing at least one life stressor, and screening positive for posttraumatic stress disorder or problem drinking. Findings highlight the critical need for disordered eating screening and prevention efforts that bolster coping skills, which can ultimately improve service member functioning and readiness.