This study investigated the relationship of religious orientation, religious affiliation, and spiritual well-being with treatment outcomes in an eating disorder inpatient treatment program. Participants were 251 women diagnosed with an eating disorder. Gain scores on the Eating Attitudes Test, Body Shape Questionnaire, Outcome Questionnaire 45.2, and therapist improvement ratings were used as outcome measures. Multiple regression analyses revealed that neither intrinsic religiousness nor religious affiliation were associated with treatment outcomes. Pearson correlations revealed that improvements in spiritual well-being during treatment were significantly associated with positive gains in eating attitudes, less body shape concerns, and positive psychological and social functioning.