Attention deficit hyperactivity disorder (ADHD) is caused by an abnormality in the development of the central nervous system. Children with attention and executive function difficulties often need long-lasting rehabilitation and there is an increasing need for timely, cost-effective, and feasible rehabilitation interventions, where the training is targeted to support everyday life functional capacity. The use of Virtual Reality (VR) in the rehabilitation of children with attention and executive function deficits offers opportunities to practice skills required in everyday life in environments emulating real-life situations. The major aim of this research project is to develop a novel effective VR rehabilitation method for children with deficits in attention, activity control and executive functions by using the virtual environment that corresponds to the typical everyday life. In this randomized control study VR glasses are used to present the tasks, and the levels of difficulty are adjusted according to the child's progress. Researchers expect that; 1) Intensive training improves the attention regulation, activity control skills and executive functions of the children in the intervention group; 2) Training of executive skills with motivating tasks in a virtual environment that is built to meet challenging everyday situations transfers to the child's everyday life, 3) The duration of the training effect does not depend on the success of the VR training itself, but on how well the child adopts new strategies that make everyday life easier and how the parent is able to support the child's positive behaviour in everyday life.