In 1995, Ron Scollon (citing Goodwin, 1994) remarked that “research methodology is a cover term for day-to-day practices which are often less well formed than our ﬁnal research reports suggest” (Scollon, 1995, p. 381). This is problematic, in the sense that “the validity of any discipline is predicated on the assumption that the research methods used to gather data are sufﬁciently understood and agreed upon” (Gass, Cohen, & Tarone, 1994, p. xiii). For the discipline of applied linguistics, a fundamental change in perspective (if not practice) would appear to be underway in its research, from an essentially unquestioned reliance on and preference for quasi-experimental studies employing parametric statistics in the 1980s, to a broader, multidisciplinary perspective on research methodology, as well as the nature of research itself, in the 1990s and to the present time. The ﬁeld seems to be struggling with a redeﬁnition of its research goals, methods, and paradigms, as can be seen in terms of our growing acceptance of qualitative methods (e.g., Lazaraton, 1995), our increasingly pointed questions about the signiﬁcance of our research (e.g., Hamp-Lyons, 1998; Rampton, 1997), and our continuing explorations of alternatives in our research (e.g., Cumming, 1994). This chapter proposes to analyze the status of quantitative research in applied linguistics by:Overviewing the nature of quantitative research in second language learning and teaching in the last 20 years by surveying the literature on research methodology published in four applied linguistics journals (Language Learning, Modern Language Journal, Studies in Second Language Acquisition, and TESOL Quarterly) and in scholarly books to ascertain what applied linguists are and have been saying about quantitative research methods.