The purpose of this study was to estimate the longitudinal and reciprocal predictive relations between children's social skills, measured by an adaptation of the frequently used Social Skills Rating Scale, and their standardized academic achievement. A large nationally representative sample of elementary school students were assessed at least annually from kindergarten through fifth grade in the Early Childhood Longitudinal Study, Kindergarten Class of 2010-2011 (n = 7963). Structural equation modeling was used to test a panel model of teacher-rated interpersonal and self-control skills and children's scores on standardized reading, math, and science achievement tests. Reciprocal relations between children's social skills and achievement were supported throughout elementary school, with achievement showing a stronger and consistent pattern of influence on children's subsequent social skills.