The aim of this study was to examine the effects of the Family-Based Health Behavior Development Program (FHEBIP) on obesity risk factors and body mass index (BMI) to prevent the increasing prevalence of overweight and obesity in children. The randomized controlled trial sample consisted of 96 fourth-grade primary school students and their mothers in Aksaray province. Data were collected using questionnaires and the Family Nutrition and Physical Activity Scale, and height and weight measurements were taken. Ethics committee and institutional approvals were obtained.