Children and youth inactivity and sedentary at school is increasing. This means that some of the students have a significant unhealthy lifestyle with physical inactivity, which in turn implies risks of suffering from various diseases, including obesity, type 2 diabetes and cardiovascular disease, all related to a sedentary lifestyle. To prevent illness, it is important that children and young people early get a positive attitude towards physical activity.The purpose of this study was to study the causes of child and adolescent physical inactivity in school, based on teachers 'and parents' perspectives.A qualitative research has been selected. To achieve the study objectives, the author has conducted seven semi-structured interviews, with an appropriate choice of five teachers and two parents with children in school. Data was analyzed with a manifest content analysis.The results show that teachers and parents felt that physical activity is a protective factor for children's health.