Eating Disorders (ED), characterized by an excessive preoccupation with eating, body shape, and weight, as well as maladaptive eating behaviors, are frequently comorbid with other psychopathologies. One of the most commonly co-occurring psychological disorders is Obsessive-Compulsive Disorder (OCD). Numerous factors contribute to the high comorbidity, ranging from biological to psychological mechanisms. Among the psychological factors, obsessive beliefs have been identified as one of the key components in explaining this high comorbidity rate. Although obsessive beliefs are common across various psychological disorders, including ED and OCD, the content of these beliefs appears to differ depending on the specific disorder. Accordingly, it has been suggested that examining obsessive beliefs in a disorder-specific manner may provide a more precise understanding of their role in the development and/or maintenance of psychological symptoms. In line with this perspective, the present study aimed to investigate the relationship between ED-specific obsessive beliefs and ED symptoms, and to examine the mediating role of emotional distress and the moderating role of cognitive fusion in this relationship. For this aim, data were collected from 559 participants aged between 18 and 65 years. Participants completed the Obsessive Beliefs Questionnaire-Eating Disorder Version, the Eating Disorder Examination Questionnaire-13, the Positive and Negative Affect Schedule, and the Cognitive Fusion Scale. Moderated mediation analyses were then conducted. Results indicated that while ED-specific obsessive beliefs predicted ED-symptoms, they did not directly predict emotional distress. However, the interaction of ED-specific obsessive beliefs with cognitive fusion predicted emotional distress, which, in turn predicted ED symptoms. The findings obtained were discussed in the light of the literature.