A significant number of studies have examined the cognitive components of basic academic skills, which has led to major changes in both teaching and early identification assessment practices. However, the majority of previous research has focused solely on reading. This study examines the cognitive components of academic writing skills across early grade levels (1-4) while controlling for basic word identification skills. Results from this study suggest writing skill requires several cognitive skills of differing emphasis depending on the level of writing skill. Perceptual and rapid perceptual processing skills are important during the early acquisition of writing skills followed by a transition to language and language retrieval skills and later still to working memory skills. Applications for education and cognitive assessment are discussed.