Although Firth and Wagner (1997) did not explicitly discuss the issue of identity in second language acquisition (SLA) research, their article was symptomatic of a general trend to open up SLA to social theory and sociological and sociolinguistic research, which in turn led some researchers to explore links between second language (L2) learning and identity. In this article, I discuss empirical research linking L2 learning and identity that has been published since Firth and Wagner. I begin with a discussion of the broadly poststructuralist approach to identity, which has become the approach of choice among researchers taking this line of enquiry. I then critically review key publications carried out in three distinct L2 learning contexts: naturalistic, foreign language, and study abroad. I conclude with some suggestions about future directions for identity-in-SLA research.