--- - |2 Abstract The aim of this study was to investigate whether indirectly and directly assessed disorder‐relevant attributes moderate the body mass index (BMI) curves over the course of treatment in anorexia nervosa, as is predicted by dual process models. The moderating role of two Implicit Association Tests (IAT) and of two questionnaires assessing aspects of striving for perfection was examined in 27 patients by means of linear mixed models. The Aiming at Perfection Single Category‐IAT and the directly assessed achievement striving dimension of perfectionism moderated patients' BMI curves over the course of treatment. Moreover, the Single Category‐IAT predicted the outcome variable over and above the directly assessed attribute. Experiencing oneself as more achievement striving compared to others at an automatic level predicted a faster weight gain. These findings show that aspects of multidimensional perfectionism—assessed at the automatic and at the reflective level—predict treatment outcome in anorexia nervosa. - European Eating Disorders Review, EarlyView.