Maternal perception of child's nutritional status has a potential impact on the identification, prevention, and treatment of childhood overweight. Thus, the aim of this study was to evaluate the prevalence of misperception and factors associated with maternal perception of the nutritional status of first- to third-grade elementary school students from private schools in the Federal District, Brazil. This cross-sectional study was conducted with 554 mother-child pairs. Children's nutritional status was assessed by measuring their weight and height. The mothers completed an online questionnaire about sociodemographic data, maternal nutritional status, maternal perception of her own nutritional status (silhouette scale for female adults), and maternal perception of child's nutritional status (silhouette scale for children). Only 30.0% of the mothers were successful in choosing the most appropriate silhouette to represent child's nutritional status. Highly educated mothers (Adjusted OR = 1.51) and mothers of male children (Adjusted OR = 2.53) or of non-overweight children (Adjusted OR = 1.65) were more likely to underestimate child's nutritional status. Conversely, mothers below 35 years of age (Adjusted OR = 1.85) and mothers of female children (Adjusted OR = 2.24) or of overweight children (Adjusted OR = 1.94) were more likely to overestimate child's nutritional status. There was a high prevalence of misperception, which shows the need for interventions for children that take into account the relevance of mother's role and the adequate recognition of child's nutritional status.