This article presents the results of three separate studies of literacy teaching and learning in the U.S. that explore the social functions of language, specifically focused on the identity development of literacy learners and teachers. Each study offers a detailed account of how literate identities are constructed and enacted and the positive and negative consequences that occur for teachers and students when they are enacted. Taken together, these three studies demonstrate how teachers' and students' understandings of identity can promote or inhibit literacy teaching and learning. (Contains 5 tables.)