The purpose of this study was to explore the role of students' use of writing strategies in light of their English writing achievements in Taiwan. This research used a cognitive approach to examine the process of writing. Forty student writers (including 20 low and 20 high achievers) in Taiwan participated in this study. Strategies used for writing by high and low achievers as revealed by a concurrent think-aloud protocol and immediate retrospective interviews with students were investigated, analysed, and compared. Results indicated that compared to low-achieving student writers, high-achieving student writers were more aware of and focused more on formulating their position statement in planning, generating text, and revising and editing their text, such as changing the meaning and fixing grammatical and spelling errors during their review. The findings are discussed in light of writing strategies and implications for writing pedagogy and teacher education. (Contains 2 tables.)