Information technology (IT) use has become essential to how individuals interact with the world. From ordering meals to taking classes or consulting a physician, so many aspects of daily life are bound up with IT that effective participation in the world demands IT use. The ubiquity of IT in work and personal lives has created a shift from IT as a tool to IT as a basis of identity formation and verification, making it fundamental to how we see ourselves and act in the world. The essential role of IT use in all aspects of daily life and social interactions has drawn information systems (IS) researchers' focus to identity issues. In this stream, IS scholars have examined IT implementation and usage as a determinant of identity, a medium for communicating and protecting identities, and how identities influence IT use. In recent years, IT use as identity has garnered interest. The IS literature on identity is rich and varied. There is substantial research interest in understanding the complex and constantly changing relationship between people and IT. To facilitate new theorizing, this monograph provides a review of diverse perspectives on IT use and identity. This work reviews 90 conceptual and empirical IS studies and identifies major themes, examines their theoretical foundations, and suggests an agenda for future research on IT use and identity.