The chapter traces the development of the construct of autonomy in language learning, including its relationship with aspects of knowledge about language, since the 1970s. It distinguishes between two broad theoretical orientations: one which focuses on learning systems in which learners take decisions about the content and processes of their learning and one which focuses on the cognitive and metacognitive capacities which enable learners to take responsibility for their learning. It also identifies key theoretical and thematic shifts and their implications for research and practice. Recognition that learner autonomy rarely involves learners learning in isolation led to its exploration via sociocultural frameworks, as a dynamic, situated construct, which is operationalised in ￼multifarious ways. Although early developments in the field began in self-access learning, this quickly shifted to include research and practice in classroom contexts, introducing a new focus on the teacher and the construct of teacher autonomy. Development of pedagogy for autonomy included critical perspectives on learner and teacher autonomy, related to notions of external and internal constraints (including learner and teacher beliefs), power relationships, and (languages) education as empowerment and transformation. The chapter also shows how autonomy has been explored in relation to other constructs, such as motivation and identity, and in the context of rapid technological development, while acknowledging the various challenges to its operationalization. Finally, it argues that future developments in the field must engage with the increasing complexity of the twenty-first century globalized world, by building on new interdisciplinary, ecological, and spatial approaches to research and practice.