This article draws on a study that investigated an implementation of reading-to-learn pedagogy (R2L) on EFL students' writing. The study involved a group of Year 8 students from an Indonesian public school who were taught English using R2L strategies that had been specifically developed for EFL classrooms, where both L1 and L2 are used as the instructional language. Classroom observations, student writing, and interviews were collected as the data. The texts produced by the students before and after the programme were examined qualitatively using a functional linguistic model. The study found that fine-tuning R2L by systematizing the use of L1 and L2 in the classroom interactions can assist in improving student writing. Students wrote longer texts, used high-level vocabulary, and had a better mastery of English grammar as shown by their use of more complex grammatical structures. Other pedagogic gains from the programme are also discussed.