In this review article on identity, language learning, and social change, we argue that contemporary poststructuralist theories of language, identity, and power offer new perspectives on language learning and teaching, and have been of considerable interest in our field. We first review poststructuralist theories of language, subjectivity, and positioning and explain sociocultural theories of language learning. We then discuss constructs of "INVESTMENT" and "IMAGINED COMMUNITIES/IMAGINED IDENTITIES" (Norton Peirce 1995; Norton 1997, 2000, 2001), showing how these have been used by diverse identity researchers. Illustrative examples of studies that investigate how identity categories like race, gender, and sexuality interact with language learning are discussed. Common qualitative research methods used in studies of identity and language learning are presented, and we review the research on identity and language teaching in different regions of the world. We examine how digital technologies may be affecting language learners' identities, and how learner resistance impacts language learning. Recent critiques of research on identity and language learning are explored, and we consider directions for research in an era of increasing globalization. We anticipate that the identities and investments of language learners, as well as their teachers, will continue to generate exciting and innovative research in the future.