ObjectiveBody image-related psychological flexibility is considered an important positive process in the field of body image, associated with lower levels of psychological distress. The present study hypothesised body image flexibility as a relevant construct in the study of body dysmorphic disorder (BDD). A mediation model was proposed, exploring if body image flexibility mediated the relationship between shame - a core construct of BDD symptomatology - and dysmorphic concern and anxiety while controlling for age and BMI.MethodsThe sample comprised 477 Portuguese-speaking participants from the general population - male and female, who completed a set of self-report measures.ResultsFemales presented significantly higher levels of dysmorphic concern (d = .42). All main variables under study were significantly correlated, with dysmorphic concern presenting positive correlations with internal shame, external shame, and anxiety, and a negative and weak correlation with body image flexibility. Path analysis results indicated that body image flexibility mediated the relationship between shame, in its internal dimension, and dysmorphic concern and anxiety, explaining 34% of the variance of dysmorphic concern and 24% of anxiety. The model was invariant across biological sex.ConclusionsOur results support the pervasive association between internal shame and dysmorphic concern, and indicate body image flexibility as a relevant emotional process in this relationship. What is already known about this topic: Dysmorphic concerns (or body dysmorphia-related symptoms) are distressing and can cause significant suffering.Shame is a core construct of BDD symptomatology, but positive processes that are involved in this relationship have been understudied.Body image-related psychological flexibility is an important emotional process in the field of body image-related difficulties.What this topic adds: Further confirms the pervasive association between shame, particularly internal shame, and dysmorphic concern.Body image-related psychological flexibility is an emotional process that mediates this relationship.Supports interventions that target body image-related psychological flexibility for BDD and associated symptomatology.