This study aimed at studying the relationships between different social determinants, overweight, migration background, lifestyle factors, and neighborhood characteristics in children and adolescents aged 6-14 years. Data were collected within the Kiel Obesity Prevention Study (KOPS). The lower the social status, the higher the prevalence of overweight (e.g., parental education low/middle/high,%: 18.4/13.6/7.9). Non-German children are twice as often overweight as German children (20.2% versus 11.7%) with a social gradient in overweight (%: 26.0/28.2/17.2). There are social differences in health-related behavior between the social groups and also between German and non-German children of the same social group. The social gradient in overweight is, in part, independent of lifestyle factors. Neighborhood characteristics like high food supply and traffic density add to the development of overweight. To summarize, overweight is a social issue; direct prevention has to address the social determinants of health as well as families with migration background. In addition, the development of "healthy" neighborhoods may support the prevention of overweight.