Self-perception of weight status and its association with weight-related knowledge, attitudes, and behaviors among Chinese children in Guangzhou.

•Over one third of children misperceived their weight status in Guangzhou, China.•Underestimation of body weight was much more prevalent than overestimation.•Underestimation was common in younger children, girls, and those with obese parents.•Children perceived as underweight/overweight had a higher intention to change weight.•Children perceived as normal weight behaved more healthily on certain behaviors.