Objective. Firstly, to investigate the degree of concern parents feel about their children's weight (parental concern). Secondly, to identify factors that influence this concern, and to test a model of parental concern using structural equation modeling. Subjects. A total of 347 non-overweight, overweight, and obese children (aged 6–13; Mean =9.5, SD =1.8) and their parents. Methods. Children and their parents attended an assessment session during which they were weighed and measured. Parents were administered a structured interview, which included the Eating Disorder Examination, and completed the Pediatric Quality of Life Inventory (parent proxy), and the Children's Body Image Scale. Results. Eighty-two percent of parents of overweight children, and 18% of parents of obese children reported little parental concern. Higher parental concern was associated with higher child Body Mass Index, less parental underestimation of child body size, and lower child health-related quality of life. Conclusions. Interventions targeting childhood obesity should aim to optimise parental concern by reducing parents’ underestimation of child body size and increasing their awareness of the effects of overweight and obesity on children's health and quality of life.