We explored associations between lifetime eating disorder (ED) diagnoses and behaviors and menstrual dysfunction using logistic regression models. Body mass index (BMI) fully explained differences in the odds of secondary amenorrhea (SA) across diagnoses. Women with dieting behaviors had borderline significantly higher odds of SA than those without after accounting for BMI. We suggest the presence of a strong association between BMI and SA and that dieting might represent a risk factor for SA regardless of BMI and ED diagnosis.