This article analyzes the effect of bodyweight on socioemotional skills for children aged two to 12 years in Chile. Using an instrumental variable approach and a representative survey, we show that both BMI and obesity are causality related to children's socioemotional development, even after assuming that our instrument is imperfect. Although we did not find significant differences between boys and girls, we do identify heterogeneous effects by age: the weight penalty for girls starts earlier than for boys. Our findings suggest that early interventions for childhood obesity not only might generate positive impacts on children's health, but also a greater accumulation of non-cognitive human capital in the future.