In this article we explore the relationship between learner corpus and second language acquisition research. We begin by considering the origins of learner corpus research, noting its roots in smaller scale studies of learner language. This development of learner corpus studies is considered in the broader context of the development of corpus linguistics. We then consider the aspirations that learner corpus researchers have had to engage with second language acquisition research and explore why, to date, the interaction between the two fields has been minimal. By exploring some of the corpus building practices of learner corpus research, and the theoretical goals of second language acquisition studies, we identify reasons for this lack of interaction and make proposals for how this situation could be fruitfully addressed.