RESUMEN
INTRODUCTION: Disordered Eating Attitudes and Behaviours (DEABs) can impact both the mental and physical health of children. Early detection is crucial to prevent complications and improve outcomes. The Eating Attitudes Test-26 (EAT-26) is a widely used, cost-effective tool for assessing DEABs. OBJECTIVE: To evaluate the psychometric properties of the EAT-26 by analysing its factor structure, internal consistency, convergent validity, and measurement invariance across sexes in Spanish schoolchildren. METHOD: Validation study in a sample of 718 schoolchildren. The sample was randomly divided into 2 groups, each with 359 participants, and we carried out an exploratory factor analysis (EFA) and a confirmatory factor analysis (CFA) of the instrument. Subsequently, we assessed the internal consistency by means of the ordinal alpha, the convergent validity with the SCOFF questionnaire and the measurement invariance across the sexes. RESULTS: The results of the EFA and CFA supported a multidimensional structure of the EAT comprising 6 factors and 21 items. These factors underlie a second-order model of DEABs. The internal consistency was adequate for most factors. The SCOFF questionnaire showed a moderate convergent validity for most of the EAT-21 factors. We found measurement invariance across the sexes. CONCLUSIONS: The abbreviated EAT-21 scale exhibited modest and promising psychometric properties, making it a suitable instrument for assessing DEABs in both sexes in educational settings.