The present paper discusses three types of research perspective on the insider-outsider continuum: outsider research, (insider's) outsider research, and insider research. It examines the essential features of the insider-outsider distinction with reference to categories such as researcher, students, classroom context, contribution, control of condition, quality criteria, disclosure of information, and example of research. The paper concludes that the insider-outsider perspective can serve as a means of building a strong theoretical base in language teaching research that will help language teacher practitioner-researchers to situate their work within a wide variety of research types.