Objective: This study investigated the self-regulated learning (SRL) strategies employed by high school EFL learners in the Asian high school context and the associations between SRL strategies and their academic achievements. Methods: A total of 6 students in Taiwan with different academic performances participated in this study to elicit their self-learning experiences and self-regulated strategy use. The data were analyzed using the grounded theory approach by undergoing three stages: open, axial, and selective coding. The comparisons among the data and categories were repeated until no new properties or relationships emerged during the analysis, ensuring theoretical saturation. In the final selective coding stage, two themes emerged from the data sets: (1) degree of teacher directing (2) higher and lower achievers’ SRL strategies use. Results: With different degrees of teacher directing, the pattern of using SRL strategies between higher and lower achievers was revealed. Higher achievers were found to be more autonomous in adopting SRL strategies. Although lower achievers also adopt some SRL strategies, they tend to use surface cognitive strategies, including repetitive rehearsal and rote memorization, instead of deep ones, such as elaboration and organization.Furthermore, in terms of self-consequence, the result also showed that only higher achievers would reward themselves after accomplishing a certain goal and resume their learning. As for low achievers, they tend to give up learning and lose motivation after rewarding themselves. Conclusion: The findings showed that EFL participants’ SRL strategy use varied in response to the self-learning context. Pedagogical implications for future research and how EFL teachers can promote students’ SRL strategy use and English teacher training are discussed.