This article attempts to clarify what is currently known about problems related to attention deficit disorder with or without hyperactivity. (ADD/H), to examine to what extent affected students manifest violent behaviour and whether there are interventions that could contribute to reducing these behaviours. Although it is the most common behavioural problem diagnosed in childhood, ADD/H is poorly understood and difficult to identify and diagnose. Considering the scale of the phenomenon and the consequences observed on the behaviour of affected children, it is important to understand its symptoms and consequences, particularly in terms of violent behaviour. Studies tend to demonstrate that students with ADD/H are significantly more likely than the others to manifest angry, aggressive, even violent behaviour towards their peers. Such behaviour leads to situations of conflict, unpopularity, rejection by peers, and more negative attention from their teachers. Interventions giving that provide students with ways of controlling their behaviour seem particularly appropriate for helping those with ADD to reduce their aggressive and violent behaviour and to develop social skills.