We examined the growth of spelling skills in a large sample of Norwegian children (N = 228) over the first 3 years in school. The roles of phoneme awareness, letter knowledge, rapid automatized naming (RAN), visual-verbal paired-associate learning, and verbal short-term memory as predictors of later spelling skills were examined. Phoneme awareness and letter knowledge together with nonalphanumeric RAN and verbal short-term memory were independent longitudinal predictors of both word and nonword spelling. In addition growth mixture modeling suggested that individual variations in the growth of word spelling were best characterized as variations around a single trajectory, whereas growth in nonword spelling was better characterized as variations around two distinct trajectories. The results are related to current theories about the cognitive and linguistic foundations of spelling. (Contains 5 tables and 5 figures.)