Each individual represents a complex network of social relationships, starting with primary socialization by parents or caretakers (Duff, 2010; Ochs & Schieffelin, 2008). As we grow up, we get socialized into more and more social groups, including families, friendships, sports teams, religious organizations, or professional associations. These relationships shape our identity throughout our lives. Some aspects of our identity are determined for us; others we control. Some aspects are relatively constant, since societies and social groups strive for stability (i.e., preferring little or slow change); others are malleable. We present our selves in different ways across various interactional contexts (e.g., professional identity at work, familial at home). Studying another language provides a unique opportunity to reflect on our various selves, because our identities are often renegotiated when we encounter new cultures and navigate new social expectations. To delve into these issues, this chapter examines identity as a complex and dynamic phenomenon, considers the relationship between language and identity, and suggests ways for addressing these issues in the L2 classroom.