During the last 3 decades, the prevalence of obesity has tripled among persons aged 6-19 years. Multiple chronic disease risk factors, such as high blood pressure, high cholesterol levels, and high blood glucose levels are related to obesity. Schools have a responsibility to help prevent obesity and promote physical activity and healthy eating through policies, practices, and supportive environments. This report describes school health guidelines for promoting healthy eating and physical activity, including coordination of school policies and practices; supportive environments; school nutrition services; physical education and physical activity programs; health education; health, mental health, and social services; family and community involvement; school employee wellness; and professional development for school staff members. These guidelines, developed in collaboration with specialists from universities and from national, federal, state, local, and voluntary agencies and organizations, are based on an in-depth review of research, theory, and best practices in healthy eating and physical activity promotion in school health, public health, and education. Because every guideline might not be appropriate or feasible for every school to implement, individual schools should determine which guidelines have the highest priority based on the needs of the school and available resources.