Adolescence is considered a transitional stage characterized by several physical, psychological and social changes. During this period, there is an increased propensity for the emergence of emotional difficulties, especially those related to body image and eating attitudes and behaviours. In particular, shame has been pointed out as a key risk factor for body image and eating-related difficulties. However, research seems to be scarce regarding this association in adolescent samples. Therefore, the current study aimed to explore whether psychological inflexibility impacts the association between general feelings of shame with body image-related shame and eating psychopathology severity. The study was conducted with 226 adolescent girls from the community, aged between 12 and 18, who completed self-report measures. Path analysis indicated that higher levels of external shame were associated with more externalized and internalized body image shame and also with greater engagement in disordered eating behaviours. Furthermore, the model demonstrated that these relationships were mediated by increased levels of psychological inflexibility. The tested model accounted for a total of 30% and 22% of externalized and internalized body image variances, respectively, and 51% of the variance of disordered eating behaviours. These findings appear to suggest that in adolescent girls, body shame and disordered eating may emerge as defensive and maladaptive strategies to cope with general feelings of inferiority, particularly in the presence of psychological inflexibility. Also, this study highlights the importance of assessing and working underlying maladaptive processes in this association, mainly in adolescents with high levels of shame.