Overweight and obesity are a worldwide burden still in expansion and are often related to an inappropriate nutrition and a lack of physical activity (PA). The therapeutic lifestyle change of these behaviours constitutes a cornerstone in the management of weight problem. However, it appears difficult to realize programme with the goal to motivate to PA, and consequently, to increase its levels of practice. Models of motivation and behaviour change have been elaborated to help people in their lifestyle behaviour change. Among these models, we wanted to introduce, describe a model of motivation and behaviour change: the transtheoretical model. Furthermore, we explained how to handle it in order to build therapeutics education interventions to motivate the practice of PA among persons with overweight and obesity.