Correlations between serial and discrete rapid automatized naming (RAN) and reading can reveal intraword and interword reading processes. In this longitudinal study, we aimed to reveal how reading processes change across grades. A total of 181 children (Mage = 7;11 years) learning to read Dutch completed serial and discrete RAN, and word and pseudoword reading tasks in Grade 2. They were retested in Grades 3 (n = 153, Mage = 9;0 years) and 4 (n = 141, Mage = 10;2 years). For both words and pseudowords, intraword processes did not change over time. For words, we found two indications of increases in interword reading processes; a significant drop in the relation between serial and discrete reading between Grades 3 and 4, and an increase in the partial correlation of serial RAN with serial reading between Grades 2 and 3. We did not find systematic changes in interword processes for pseudowords. In all, these longitudinal findings support earlier cross-sectional findings indicating that children become more able over time to process multiple words simultaneously.