Many factors have been shown to impact treatment outcome in eating disorders, including illness related variables (e.g. symptom severity), and broader clinical features (e.g. personality pathology). Less is known about the potential impact of patient related variables, such as patients' views regarding treatment suitability and success. This study explored the impact of eating disorder severity, personality features and patient expectations regarding treatment suitability and success, on eating pathology at treatment end. Participants were 128 adults with diagnosed eating disorders who completed a course of evidence-based psychological therapy in a community eating disorders service in the UK. Patients completed measures of eating disorder psychopathology and personality features at treatment commencement, and a measure of patient expectations regarding change after session six. They repeated the measure of eating disorder psychopathology at treatment end. All patients had some level of positive expectations regarding the suitability and potential success of treatment after session six. Eating disorder severity significantly predicted eating pathology at treatment end. However, strength of positive expectations regarding treatment success significantly predicted eating pathology over and above baseline level of eating disorder severity. Personality features at baseline were not significantly related to treatment outcome. Findings suggest that patients' expectations regarding the likely success of therapy have a significant impact on treatment outcome. Patients who develop a strong belief that treatment will work may be more likely to actively engage in the process of therapy to achieve their recovery goals. These findings have important implications for the early phase of therapy and how patients are oriented towards treatment.