The functional relationships between developmental change in children's self-control and academic achievement were examined using longitudinal family data. Multivariate latent growth models (LGM) were specified to determine whether the rate of growth in academic achievement changes as a function of developmental change in self-control. Data came from the Rural Georgia Single-Parent Family Study for 140, 127, and 124 families, and 114, 120, and 102 teachers. Self-control and academic achievement were significantly associated as indicated by the significant covariance between the variables' initial status. Children who initially displayed better cognitive and behavioral self-control also initially displayed greater academic achievement. Change in these variables over time, however, was not significantly correlated. Measurement invariance was also assessed for the Children's Self-Control Scale (CSC) (L. Humphrey, 1982) and the Woodcock Johnson test. Restrictive models, based on assumptions of equality across both time and raters, yielded adequate model fit. An appendix contains the CSC. (Contains 4 figures, 7 tables, and 22 references.) (Author/SLD)