Background: Schools and parents may play important roles in preventing childhood obesity by affecting children's behaviors related to energy balance. This study examined how school nutrition policy and parental control over children's eating and physical activity habits are associated with the children's overweight/obesity (hereafter overweight) status. Methods: Data were analyzed from a total of 246 pairs of children and parents who were recruited in the 2008-2009 academic year from 10 randomly selected public secondary schools in Indiana (school response rate = 66.7%; participant response rate = 73.5%). Logistic regression analyses were performed to examine odds ratios of different levels of school nutrition policies and parental control with and without adjusting for sociodemographic characteristics. Results: Children who attended schools where soda pop (OR = 3.79, p less than 0.01) and non-low-fat salty snacks (OR = 2.46, p = 0.05) could be purchased were more likely to be obese than those at schools where such items were not sold. Children whose parents rarely or never ensured that their child was avoiding eating too many sweets (OR = 2.33, p = 0.08), avoiding spending too much time watching TV (OR = 2.24, p = 0.06), or engaging in physical activity (OR = 2.35, p = 0.09) were more likely to be obese than children whose parents did so always or most of the time. Conclusions: School nutrition policy and parental control over children's eating and physical activity habits are associated with the children's overweight status. (Contains 3 tables.)