The current study examined individual differences in children's phonological and visuospatial short-term memory as potential mediators of the relationship among attention problems and near- and long-term scholastic achievement. Nested structural equation models revealed that teacher-reported attention problems were associated negatively with composite scholastic achievement (reading, math, language), both initially and at 4-year follow-up in an ethnically diverse sample of children (N = 317). Much of this influence, however, was attenuated by phonological short-term memory's contribution to near-term achievement and visuospatial short-term memory's contribution to long-term achievement. Domain-specific reading and math models showed similar results with some exceptions. In all models, measured intelligence made no contribution to later achievement beyond its initial influence on early achievement. The results contribute to our understanding of the mechanisms associated with individual differences in children's scholastic achievement, and have potential implications for identifying early predictors of children at risk for academic failure, and developing remedial programs targeting phonological and visuospatial short-term memory deficits in children with attention problems. (Contains 5 figures and 2 tables.)