ABSTRACTBACKGROUNDThis was a cross‐sectional survey to investigate the relationship of age, parent education, sleep duration, physical activity, and dietary habits with overweight or obesity in school‐age children in Shanghai.METHODSThe survey gathered information from 13,001 children in grades 1 through 5 (age 6 to 10 years) among 26 elementary schools in 7 districts. Activity level was evaluated using the International Children's Leisure Activities Study Survey Questionnaire (CLASS‐C). The definitions of normal, overweight, and obese were adjusted for each age.RESULTSLogistic regression analysis indicated that age, being male, having ≤10 hours of sleep on non‐school days, eating ≥1 vegetable/day, or drinking ≥1 sugar‐sweetened drink/day increased the risk for a child being overweight or obese compared with having >10 hours of sleep or ≤3 vegetables or ≤3 sugar‐sweetened drinks/month (p ≤ .008). Having >2 hours of outdoor activities on non‐school days reduced the risk of being overweight or obese compared with ≤2 hours of outdoor activities on non‐school days (p < .001).CONCLUSIONSWe found that age, sex, sleep, and some dietary habits impacted weight, and suggests that specific cultural and economic factors may impact risk of a child being overweight or obese.