The objectives of the study were to analyze the psychometric properties, factor structure and internal consistency of the Spanish version of the Thought-Shape Fusion Questionnaire (TSF-Q), as well as to determine its validity by evaluating the relationship of the TSF-Q to different instruments. Two groups were studied: one comprising 146 patients with a diagnosis of anorexia (n = 82), bulimia (n = 33) or unspecified eating disorder (n = 31), and another group of 115 undergraduates with no history of psychological disorder. All participants completed the TSF-Q, TAF-Q, EDI-2, STAI, BDI and SCL-90-R. Differences in TSF-Q scores between the diagnostic subgroups were also analyzed. Two factors were obtained which coincided with the two sections indicated by the authors of the questionnaire: conceptual and interpretative. The internal consistency of the TSF-Q and its subscales was determined by means of Cronbach's alpha, with values ranging between .93 and .96. The correlations with other instruments reflected adequate validity. There were no significant differences between the diagnostic subgroups. The Spanish version of the TSF-Q meets the psychometric requirements for measuring thought-shape fusion and shows adequate internal consistency and validity.