Objective: Children and parental awareness regarding weight is linked to the development and management of overweight and obesity. The aim of this study is to assess the actual weight, perceived weight, and desired weight of Romanian school children. Methods: A cross-sectional study was conducted in 2019 in seven schools from two counties of Romania and included 880 pupils aged between 10 and 15 years old and 665 parents. We administrated confidential questionnaires to the participants, and we measured children’s weight and height during school activities. Results: A total of 61.0% of pupils had normal weight, 7.4% were underweight, and 31.6% were overweight or obese. A total of 66.7% of normal weight children, 56.5% of overweight children, and 40% of underweight children perceived their weight accurately. Regarding parents, a majority correctly appreciated the weight of their normal weight children and only a third appreciated correctly the body weight of their underweight and overweight children. Factors such as body mass index, gender, weight related behaviors, parents’ estimation about their children’s weight, discussions of weight topics inside family, and bullying, cyberbullying and exclusion from groups were associated with misperceptions. Conclusion: The study provides useful information for health education activities targeting both children and their parents regarding appropriate body weight management of children.