Although school attainment is a cumulative process combining mastery of both academic and behavioral skills, most studies have offered only a piecemeal view of the associations between middle-childhood capacities and subsequent schooling outcomes. Using a 20-year longitudinal data set, this study estimates the association between children’s academic skills, antisocial behaviors, and attention problems—all averaged across middle childhood—and their long-term educational outcomes. After adjusting for family and individual background measures, we find that high average levels of math and reading achievement, and low average levels of antisocial behavior problems, are positively associated with later attainment. Associations between attention problems and attainment are small. Associations are attenuated somewhat when sibling differences in these skills and behaviors are related to sibling differences in attainment outcomes.