Background <p>Weight suppression (WS), traditionally defined as the difference between highest past and current weights at adult height, is a correlate and predictor of eating disorder (ED) psychopathology. However, for growing adolescents, it may be more appropriate to use a developmentally-adjusted calculation of WS. This study compared how developmental WS, calculated using <i>z</i>BMIs, compared with traditional WS, calculated using weights, as correlate of ED psychopathology in treatment-seeking adolescents with transdiagnostic EDs.</p> Methods <p>Adolescents with EDs (<i>N =</i> 93) completed the Eating Disorder Examination Questionnaire (EDE-Q) at presentation to outpatient care. Weight histories were extracted from medical records. Regressions examined the association between each measure of WS and EDE-Q scores, adjusting for ED diagnosis. Dominance analyses with bootstrapping assessed whether developmental WS outperformed traditional WS.</p> Results <p>Developmental WS negatively associated with EDE-Q Shape (<i>sr</i>^<i>2</i> <i>=</i> 0.05, <i>p =</i>.020) and Weight Concern (<i>sr</i>^<i>2</i> <i>=</i> 0.05, <i>p =</i>.021). In contrast, traditional WS did not associate with any EDE-Q scores. Although dominance weights were larger for developmental WS compared to traditional WS, bootstrap sampling revealed no significant differences in magnitudes.</p> Conclusions <p>Results preliminarily support developmental WS as a correlate of body image concerns in youth with EDs, though replication is needed.</p>