Background: Levels of aggression are high in residential settings for juveniles with Mild Intellectual Disability (MID). As a result, treatment is less effective, aggression causes injury, traumatic experiences and longer inhabitation for juveniles. Additionally, inpatient aggression has been linked to burnout and stress among group workers, which has negative consequences such as less job satisfaction or poorer work performance Objective: Therefore, it is crucial to diminish aggressive incidents in these settings and to find a way for staff how to respond to aggression properly. Methods: As there is no intervention method which tackles all of the referred problems efficiently, a new method Non-violent Resistance for MID was introduced into three residential settings for juveniles with MID, in a quasi-experimental stepped wedge design. Reports of aggressive incidents were assessed seven times before, during and after the training in NVR-MID on group level. Multilevel analyses were carried out in order to assess the development of the aggressive incidents over time. Results: Aggressive incidents decreased significantly in time during and after training in NVR-MID, this decrease is seen in all three institutions. Thus, regardless of resident’s age, gender or IQ, NVR-MID seemed successful in diminishing aggressive incidents. Furthermore, a significant interaction effect was found between institution and time, indicating that regardless if incidents of aggression were relatively high at baseline, decrease in incidents was similar to institutions where incidents were relatively low on baseline. Conclusions: Implementing NVR-MID into residential settings for juveniles with MID and comorbid behavioral problems might help to decrease aggressive incidents.