Access to core subject-area curriculum for students from immigrant backgrounds who are learning the dominant language of instruction has long been a barrier to equitable education around the world, especially in secondary schools. This article explores the promise of Complex Instruction (CI) to address barriers to access for such multilingual learners, demonstrating what they were able to do with language, literacy, and academic content in CI classrooms in one middle school in California. The article illustrates how the curricular and pedagogical structures of CI classrooms facilitated multilingual learners' academic engagement and opportunities for language development. It also warns that in order to recognise multilingual learners' successes, teachers' conceptions of language and literacy may have to change.