L2 learners' development of pragmatic ability has been studied from a variety of theoretical perspectives. This paper seeks to assess the contributions made by different approaches to interlanguage pragmatics as a subfield of Second Language Acquisition. A first approach locates the development of pragmatic ability within a comprehensive model of communicative competence, either examining pragmatics as an autonomous component or in its interaction with grammatical ability. The discussion focuses on the evidence for and against the interdependence of pragmatic and grammatical ability. A second perspective explores pragmatic learning as information processing, with a particular view to the roles of attention, awareness, input, and metapragmatic knowledge. One important question requiring further exploration is whether principles of grammar learning extend to the learning of pragmatics. A third approach investigates pragmatic learning in sociocultural perspective. A key observation has been that pragmatic knowledge emerges from assisted performance, both in student-teacher and peer interaction. The fourth approach is language socialization, investigating how cultural and pragmatic knowledge are jointly acquired through learners' participation in recurring situated activities. In a final section, the paper discusses whether the four perspectives are compatible or mutually exclusive.