The aim of the study was to compare a clinical sample with eating disorders to different control samples on self-report measures of metacognition and eating disorder symptoms, in order to investigate the role of metacognition in eating disorders.The clinical group consisted of 53 female patients with eating disorders who completed the Metacognitions Questionnaire-30 and the Eating Disorder Examination Questionnaire 6.0. One-hundred and fifty women who served as a control group completed the questionnaires as an Internet survey. This control group was divided into three groups based on self-reported history of eating and psychiatric problems (N=47), other psychiatric problems (N=37), or no such problems (healthy controls: N=66).The clinical group scored significantly higher on dysfunctional metacognition than healthy controls, especially on “negative beliefs about uncontrollability and danger”, “need to control thoughts”, and total MCQ-30 score. Eating disorder symptomatology was positively correlated with metacognition. Metacognition explained 51% of the variance in eating disorder symptoms after controlling for age and BMI, with “need to control thoughts” as the most important factor.Metacognitive beliefs may be central in understanding eating disorders, and metacognitive treatment strategies could be a promising approach in developing new psychological treatments for eating disorders.