To test whether overvaluation of shape/weight at the end of treatment prospectively predicts relapse at 12-month follow-up in patients with binge-eating disorder (BED). Participants were 129 patients with BED who achieved abstinence from binge eating after 6 months of behaviorally-based weight-loss treatments in a clinical trial. Independent assessments conducted at posttreatment and at 12-month follow-up included the Eating Disorder Examination interview, the Beck Depression Inventory, and weight measurements. Of the 129 participants who attained abstinence from binge-eating at posttreatment, 46 (36%) were categorized with clinical overvaluation and 83 (64%) with subclinical overvaluation; 115 (89%) were re-assessed at 12-month follow-up. Participants with overvaluation at posttreatment were significantly more likely than those without to relapse at 12-months to non-abstinence from binge eating (54% vs. 28%) and to diagnosis-level binge-eating frequency of once weekly or greater (31% vs. 13%). Overvaluation at posttreatment predicted significantly higher eating-disorder psychopathology and depression scores at 12-month follow-up but were unrelated to weight and weight changes. Treatment groups did not have main or interaction effects; posttreatment overvaluation effects were observed regardless of treatment and of covarying for posttreatment value of dependent variables. Our findings suggest that overvaluation of shape/weight at the end of treatment predicts relapse and heightened eating-disorder psychopathology and depression scores 1 year later in patients who achieved abstinence from binge eating with behaviorally-based treatments. Overvaluation of shape/weight has significant clinical implications and warrants consideration as a diagnostic specifier for BED as it provides important prospective prognostic information. Although effective treatments are available for binge-eating disorder, relapse following successful treatments is not uncommon. Almost nothing is known about what predicts relapse following treatments for binge-eating disorder. Our study found that overvaluation of shape/weight (i.e., body image concerns that overly impact self-worth) at posttreatment prospectively predicted relapse and higher eating-disorder psychopathology and depression 1 year later in patients who achieved binge-eating abstinence with behaviorally based treatments. gov registration: NCT00829283. (Treatment of obesity and binge eating: Behavioral weight loss vs. stepped care.).