Purpose <p>This study aimed to validate a core beliefs model of disordered eating in a sample of adults with a current eating disorder diagnosis. This model outlines important processes and pathways from maladaptive eating disorder core beliefs to dietary restraint, objective binge eating and compensatory behaviours.</p> Methods <p>Participants were adults (<i>N</i> = 232) living in English-speaking countries who self-reported having a current eating disorder diagnosis given by a healthcare professional. Preliminary analyses included examining correlations between included variables and internal consistency. Path analysis was conducted in R to test the core beliefs model.</p> Results <p>The original model demonstrated poor to acceptable fit to the observed data. Minor modifications were utilised to remove non-significant paths to improve fit, including the removal of ‘perfectionism’ as a mediating variable in the model. The final modified model indicated acceptable model fit. This model demonstrates specific pathways that maladaptive core beliefs contribute to the development of dietary restraint, objective binge eating and compensatory behaviours, through either increased pre-occupation with eating, weight and shape, or through increased negative affect, emotional dysregulation and meta-cognitive beliefs about binge eating.</p> Conclusions <p>The present study provides partial validation of a core beliefs model of disordered eating and extends the current understanding of how maladaptive core beliefs may impact the development of key disordered eating symptomatology.</p> <p>Level of Evidence: IV.</p>