We examined the developmental trajectories and cognitive predictors of first language Chinese reading, second language English reading, and mathematics skills in Hong Kong children in Grades 1-5. We used longitudinal data of 1,000 children (M[subscript age] = 7.59 years) assessed on phonological awareness, rapid naming, and morphological awareness in Grade 1 and Chinese word reading, English word reading, and arithmetic calculations in Grades 1-5. Results revealed a decelerating growth pattern for word reading in Chinese and English and a linear growth pattern for arithmetic calculations. Rapid naming and morphological awareness predicted the initial status of all academic skills. The findings suggest that although these academic skills share initial cognitive processes, they follow remarkably different developmental trajectories.