This research aims to study the development of ninth grade students' reading and writing abilities and interests in learning English taught through computer-assisted instruction (CAI) based on the top-level structure (TLS) method. An experimental group time series design was used, and the data was analyzed by multivariate analysis of variance (MANOVA) with repeated measures as well as basic statistical and line graphs. The results demonstrate that the experimental group attained significantly higher development in English reading and writing at the 0.001 level and registered significantly higher interests at the 0.01 level.