Objectives: The aim of this study was to evaluate the levels of physical literacy (PL) in school children (10 to 16 years) in Santiago, Chile, and to explore the relationship between PL and body mass index (BMI). In addition, gender and age differences were analyzed in relation to PL levels in a context where childhood obesity remains a public health challenge. Methods: A total of 439 students in grades 5-8 were assessed using the Canadian Assessment of Physical Literacy-2 (CAPL-2) questionnaire. Demographic variables (sex, age, and BMI) were correlated with levels of motivation to engage in physical activity and physical activity knowledge. Chi-square and effect size were applied. Results: The results revealed a significant correlation between motivation for physical activity and gender, with boys showing higher levels of motivation than girls (chi(2) = 12.403, p < 0.006). In addition, an inverse relationship was observed between BMI and motivation (effect size = 0.198), suggesting that more motivated children tend to have a healthier BMI. Knowledge about physical activity increased with age (chi(2) = 60.460, p < 0.001) but did not have a significant influence on BMI. Conclusions: The findings highlight the need to design gender-specific interventions that enhance motivation as a key factor in promoting a healthy lifestyle and physical activity adherence. Public health strategies should include motivation-driven approaches to foster physical literacy and long-term engagement in physical activity, particularly for girls, to address pediatric health challenges in Chile. Public health policies should address these factors to improve pediatric health outcomes.