Objective The objective is to evaluate a body and movement‐oriented intervention on aggression regulation, specifically aimed towards reducing anger internalization in patients with an eating disorder. Method Patients were randomized to treatment‐as‐usual (TAU) plus the intervention (n = 38) or to TAU only (n = 32). The intervention was delivered by a psychomotor therapist. TAU consisted of multidisciplinary day treatment (3–5 days per week during 3–9 months). Anger coping (Self‐Expression and Control Scale) and eating pathology (Eating Disorder Examination‐Self‐report Questionnaire) were measured at baseline and follow‐up. Differences between pre‐intervention and post‐intervention scores were tested by using repeated measures ANOVA. Results The intervention group showed a significantly larger decrease of anger internalization than the control group (η2 = 0.16, p = 0.001). Both groups showed a significant reduction in eating pathology, but differences between groups were not significant. Discussion A body and movement‐oriented therapy seems a viable add‐on for treating anger internalization in patients with an eating disorder. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.