A longitudinal-correlational design was used to test the hypothesis that individual differences in rapid automatic naming make a unique contribution to explaining the growth of orthographic reading skills in 2 overlapping periods of development: second to fourth grade, and third to fifth grade. Separate analyses were done on the entire sample of approximately 200 children as well as on subsamples selected for impairment in word-reading development (bottom 20% and bottom 10% of readers). When second- and third-grade reading skills were not included in the multiple regressions, both rapid automatic naming and phonological awareness skills were strongly predictive of individual differences in reading 2 years later. With prior levels of reading skill included in the predictive equation, rapid automatic naming ability did not uniquely explain variance in any of the reading outcome measures. In contrast, individual differences in phonological awareness in both second and third grades did uniquely explain growth in a variety of reading skills over this developmental period. Results are discussed in the context of methodological issues in the use of longitudinal-correlational designs to study reading growth.