Despite a growing recognition of the importance of teacher beliefs and practices, those of novice EFL secondary teachers regarding writing instruction remains underexplored. Drawing on complexity theory, this article reports on two secondary teachers’ beliefs and practices about writing instruction in Macau. Data were gathered through classroom observations, in-depth interviews and documents. The findings reveal two distinctive systems of beliefs and practices within the two cases, one being element-based and the other being process-oriented. Specifically, while the teacher of element-based beliefs experienced difficulties in enacting key elements of genre, audience, and feedback in practice, the teacher of process-oriented beliefs adopted a step-wise approach in instructional practice, which was nonetheless constrained by the school curriculum. These findings suggest that while the two cases were able to maintain internal coherence between their individual beliefs and practices, they experienced external constraints stemming from their curriculum and schools that led to dissonances in their beliefs and practices. The study calls for attention to the complex interactions among beliefs, practices and contexts and to how novice teachers develop their beliefs and practices systems regarding writing instruction within their situated contexts.