In this article the authors report on the use of a scaffolding pedagogy (Gibbons, 2009), informed by systemic functional linguistics, to support the writing of English language learners in middle years curriculum learning. They focus on the work of one teacher and her English class across the first 18 months of a longitudinal design-based literacy research project, Embedding Literacies in the Key Learning Areas (ELK). This 3-year project was conducted in an Australian urban secondary school with 97.5% of students from language backgrounds other than English. A core aspect of the pedagogy implemented through the ELK project is the use of a shared metalanguage to make visible the patterns of language valued for discipline learning. Analysis of instructional materials, classroom discourse, and data on students' achievement on standardized external and formative internal assessments of writing over 18 months indicates that growth in writing is related to pedagogical practices that include consistent use of a functional metalanguage in classroom modeling of exemplar texts and in feedback on students' writing.