Despite high prevalence of childhood overweight and obesity, recent studies document that 70-80% of overweight children underestimate their weight status. Weight status misperception (underestimation and overestimation of weight) is conceptualized as the discrepancy between actual (measured) and self-perceived weight status. However, quantication of weight status misperception remains challenging. To facilitate easier interpretation, we propose a novel approach to quantify weight status misperception using Stunkard and Truby’s body rating-scale and weight status categories (according to World Health Organization cut points) from measured height and weight among grade 5 students in Nova Scotia. In this study our main focus was to investigate to what extent the overweight and obese children underestimate their weight. We used a mixed effect logistic regression, considering school level eff ect as random. One of the key challenges while executing this model was that while using the body rating scales as the tools of misperception, overweight and obese children had higher probabilities of underestimating their weights compared to the normal weight children, even if the pictures were chosen randomly. To eliminate this bias, we introduced an offset term in the model. After eliminating the bias, overweight and obese children have 23 and 37 times higher odds respectively to underestimate their weight status compared to normal weight children. The method used in this work is an advancement as it provides estimates are more accurate compared to the previous approaches.