Development of theories in second language acquisition and their relationship with teaching-learning process. This article surveys major development of theories and research in second language acquisition. Three major theories have significant impacts on research and practice in the field: behaviorism, nativism, and interactionism. Research in the area have been stimulated by the ideas of Chomsky (1957) and Corder (1967). These have led to the issues of acquisition and learning (Krashen 1983), natural acquisition order, and the roles and relationship of implicit linguistic knowledge, explicit linguistic knowledge, and other knowledge (Bialystok 1980). It is argued that teaching should be based on theories and, therefore, we should not only import theories but also conduct research in order to produce our own theories.