The prevalence of overweight and obesity has significantly increased over the past few decades and is linked to metabolic diseases across the lifespan. Its etiology has been attributed to a large number of sociodemographic, behavioral (e.g. unhealthy nutrition, low levels of physical activity), perinatal, and clinical risk factors, which are active already from childhood and adolescence. Still, their exact role, interplay, and mechanisms implicated in this process remain unclear. The trends of childhood obesity call for actions regarding the prevention and management of this disease early in life. The Special Issue "Childhood Obesity: Nutrition and Lifestyle Determinants, Prevention and Management" aims to host original articles, systematic reviews or meta- analyses that will advance the current knowledge on the role of health behaviors, especially of nutrition, on the development of overweight or obesity in childhood and adolescence, provide valuable information about the nutritional habits of overweight/obese children and adolescents, and describe novel approaches via lifestyle modification for the prevention or management of obesity in youth.