The generative approach to second language (L2) acquisition (SLA) is a cognitive based theory of SLA that applies theoretical insights developed from within generative linguistics to investigate how second languages and dialects are acquired and lost by individuals learning naturalistically or with formal instruction in foreign, second language and lingua franca settings. Central to generative linguistics is the concept of Universal Grammar (UG), a part of an innate, biologically endowed language faculty which refers to knowledge alleged to be common to all human languages. UG includes both invariant principles as well as parameters that allow for variation which place limitations on the form and operations of grammar. Subsequently, research within the Generative Second-Language Acquisition (GenSLA) tradition describes and explains SLA by probing the interplay between Universal Grammar, knowledge of one's native language and input from the target language. Research is conducted in syntax, phonology, morphology, phonetics, semantics, and has some relevant applications to pragmatics.

Some of the main questions in GenSLA include:

As generative second language research endeavours to explain the totality of L2 acquisition phenomena, it is also concerned with investigating the extent of linguistic transfer, maturational effects on acquisition, and why some learners fail to acquire a target-like L2 grammar even with abundant input. Furthermore, studying L2 acquisition through a generative lens give linguists a better idea of the natural constraints on human languages and the inner workings of Universal Grammar.

Research in generative second-language acquisition is presented at a range of conferences, including: GASLA (Generative Approaches to Second Language Acquisition), GALANA (Generative Approaches to Language Acquisition - North America), and BUCLD (Boston University Conference on Language Development).

Prominent researchers of the topic include Suzanne Flynn of MIT, Bonnie Schwartz of University of Hawaii, Antonella Sorace of University of Edinburgh, and Lydia White of McGill University.

In the late 1960s-early 1970s researchers observed that the language and errors of L2 learners were not random but systematic and evidence of rule-governed behaviour. From this observation researchers proposed the concept of interlanguage which refers to the language system used by L2 learners that contains interacting linguistic aspects of both the L1 and L2. This system theory regarding the interlanguage suggests that L2 learners have mental grammars that can be described with rules and principles.

The history of GenSLA research begins in the 1980s prompted by two interconnected questions:

The logical problem of language acquisition refers to the observable mismatch between the primary linguistic data (PLD) or language specific input a child is exposed to and the state of their eventual language system, that is, children appear to acquire their native language quickly and with little negative feedback even when the input is uneven, inconsistent and unrepresentative of their ultimate linguistic competence. Some suggest in an argument commonly known as Poverty of the Stimulus (POS) that there are, in fact, certain properties of language that are too abstract, subtle and complex to be acquired by language input and the operation of domain general cognitive mechanisms alone. Similarly, children are not exposed to a rich wealth of linguistic data to be able to acquire all the rules and principles of their distinct language. Therefore, an extra component, such as the UG which consists of innate domain-specific linguistic knowledge, is needed to account for these POV properties.