Introduction. In Spain, childhood obesity is worrying, and its development might be influenced by the family setting. The objectives were to determine the prevalence of excess weight among adolescents, evaluate family variables that could affect it, and determine parents' body perception. Population and methods. Cross-sectional study; students from five secondary schools in health area V of the Region of Murcia were included. Students' anthropometric measurements were recorded and a survey was administered to parents, including variables such as weight, height, exercise, level of education, family structure, and body perception. The analysis was done using contingency tables and the association with Somers' D measures. Results. Four hundred and twenty one students participated (age: 12.8 ± 0.6 years old); 21.1 % were overweight and 19.5 %, obese. There was an association between parent and child excess weight (Somers' D with a p value < 0.05). If both parents had a sedentary lifestyle, their children would exercise less. The higher the level of parental education, the lower the rate of childhood overweight (p < 0.05). Overweightobesity among children was higher in separated or single-parent families. In total, 32 % of parents misperceived their children's excess weight and 53 %, their own. Conclusions. In this sample, the prevalence of excess weight was 40.6 %. Parents' nutritional status, level of education, and family structure were associated with childhood obesity. Mothers had a greater influence on the development of their children's overweight. Parents underestimated obesity.