The study explored the moderating role of rapid automatized naming (RAN) in reading achievement through a cusp-catastrophe model grounded on nonlinear dynamic systems theory. Data were obtained from a community sample of 496 second through fourth graders who were followed longitudinally over 2 years and split into 2 random subsamples (validation and cross-validation groups). Results verified the superiority of the cusp-catastrophe over linear and logistic models and established RAN-digits performance as a significant bifurcation factor in both concurrent and longitudinal prediction models. These findings suggested that reduced serial naming speed below a critical level was associated with significantly reduced predictability of word reading efficiency from pseudoword decoding ability. Results were tentatively interpreted as documenting the importance of highly automatized coordination of reading-related component processes, indexed by RAN performance, for word reading efficiency during the early and middle stages of reading acquisition.