Education practitioners such as teachers play an imperative role in translating learning among students and understanding their belief systems and practices is central in the reshaping of educational policy and instructional practice. This study employed a case study design to explore teachers' beliefs and pedagogical practices in teaching second language (L2) academic writing in the context of senior high school. Two purposively selected teachers who were teaching academic writing courses in a polytechnic school in the Philippines participated in the study. Drawing from semi-structured interviews, the study revealed that the teacher participants held complex belief systems about the nature of writing and the process of teaching academic writing. While the participants shared a variety of beliefs about L2 academic writing, findings from non-participatory classroom observations showed that they tended to adhere strictly to these beliefs when enacting classroom instructions. Moreover, the participants indicated that time, class schedule, class size and school facilities were among the factors that constrained them from translating their beliefs into instructional practices. The study has practical implications to L2 writing pedagogy. Recommendations for future research are also discussed in this paper.