Research Findings: This study examined the extent to which children's development and growth in oral language and literacy skills during the early childhood period predicted writing ability in the primary grades. Participants were 313 children who were tested on a battery of oral language and literacy measures at four time points, beginning during preschool (M age = 4.2 years) and spaced approximately 6 months apart over 1.5 years. Results provided a novel contribution to the extant literature by demonstrating that both children's early skill levels and rates of growth in oral language and decoding skills predicted later spelling and written composition when children were in kindergarten or first grade. Practice or Policy: Findings suggest that in addition to having a stronger starting point (i.e., higher initial skill level), the more quickly children can further develop these skills, the more they are able to use them to write productively.