The authors examined individual differences in reading development in English and Finnish. English-speaking Canadian children were assessed once per year in Grades 1-5, and Finnish children were assessed twice per year in Grades 1-2. Results from latent growth curve and simplex analyses showed that initial status was generally negatively associated with subsequent growth and that, although stable, individual differences were more likely to significantly decrease than to increase across the measurement points. Growth mixture models identified multiple groups of children whose reading development followed distinct patterns. The results indicate that it is possible for educational systems to significantly reduce individual differences in basic reading skills during early reading development.