Overvaluation of shape and weight in binge‐eating disorder (BED) is associated with greater eating‐disorder psychopathology and greater weight‐bias internalization, which are—in turn—associated with poorer mental and physical health. Little is known, however, about the significance of other cognitive processes, such as rumination, in BED. This study examined rumination and overvaluation of shape/weight with eating‐disorder psychopathology and weight‐bias internalization among 237 treatment‐seeking patients with BED and comorbid obesity. Hierarchical multiple regressions indicated that rumination was associated with eating‐disorder psychopathology and weight‐bias internalization above and beyond the influence of overvaluation of shape/weight. Findings suggest that, among patients with BED/obesity, rumination is an important cognitive process associated with severity of eating‐disorder psychopathology even after accounting for overvaluation of shape/weight. Patients with greater rumination might be more likely to dwell on weight‐based discrimination experiences and internalize these negative attitudes. Additional controlled examination could determine whether rumination represents another potential target for BED/obesity treatment. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.