Background: Most previous studies of teaching styles and reading skills have been cross-sectional. Longitudinal research is needed to clarify the direction of effects. The present longitudinal study examined the degree to which differences in teaching styles in the third grade predict the sixth-grade reading performance. The consistency of the findings was addressed by comparing results across students in two countries (Finland and Estonia). Methods: A total of 1,057 students (50.9% boys) were followed from the third to sixth grade. Teaching styles of third-grade teachers (N = 70) were examined as predictors of the development of reading (i.e., third-grade to sixth-grade reading fluency and comprehension). Results: Five patterns of third-grade teaching practices were found across two countries: "child-centred style," "teacher-directed style," "child-dominated style," "extreme child-centred style," and "mixed child-centred" and "teacher-directed style (mixed teaching style)." The mixed teaching style and the child-centred style in the third grade were related to the greatest increases in reading fluency from the third to sixth grade, over and above the contribution of age, gender and maternal education. Conclusions: The findings underscore the importance of the flexible use of child-centred and teacher-directed practices, which are both linked to the development of reading fluency during late primary school years.