Most theories of reading development assume a shift from slow sequential subword decoding to automatic processing of orthographic word forms. We hypothesized that this shift should be reflected in a concomitant shift in reading-related cognitive functions. The current study investigated the cognitive dynamics underlying reading development in a large school sample ranging from beginning to experienced readers. The results showed that phonological awareness (PA) and rapid automatized naming (RAN) contributed substantially to reading fluency over all six primary school grades. However, the relationship between PA and word (but not pseudoword) reading fluency decreased as a function of reading experience, whereas the relationship between RAN and word reading fluency increased gradually. Moreover, this cognitive shift was most pronounced for high-frequency words. The results seem to point to the development of one (and only one) reading network for all types of words in which processing load or type of processing depends on word familiarity and amount of reading experience.