Even though social and emotional well-being has been proposed as a main goal of education, its association with academic achievement is usually overlooked, particularly considering that educational institutions are requested to show academic outcomes, and thus their focus is on cognitive development and academic training. This study adopts a multilevel perspective to test this association among Chilean elementary students, considering features at individual (socio-emotional well-being, self esteem, and social integration) and social levels (classroom social climate and social network characteristics). Results show that socio-emotional variables, and particularly teachers' ratings of their students' self esteem, are associated with academic achievement. Interaction effects of individual and contextual variables are presented, and implications for research and interventions are discussed.