This paper reviews the empirical and conceptual foundations of generative linguistics and discusses the issues that generative linguistics raises for the study of second language acquisition. Second language researchers adopting generative approaches have tended to focus on basic development questions and on the role of Universal Grammar in interlanguage morphosyntax and the syntax-semantics interface. Overwhelmingly, this research points to the conclusions (1) that the initial grammatical state in second language acquisition is equivalent to the stable grammatical state of (one of) the previously acquired language(s) and (2) that interlanguage grammars and native language grammars are epistemologically homogeneous. The paper points to two kinds of questions that remain underexplored. First, it is unclear whether the differences between the initial states of native vs. nonnative language acquisition can fully account for the observed differences in outcomes typically associated with these two learning conditions. Secondly, there is very little research on whether phonological principles of Universal Grammar guide second language acquisition. Preliminary results from a study of the acquisition of exceptional Turkish vowel harmony by speakers of English is offered as a step in this direction.