Willingness to communicate in a second language (L2 WTC) is a speaker's voluntary engagement in communication using a target language. WTC has undergone several conceptualisations over the past twenty years or so. The aim of the current article is to present a narrative review of the major conceptual developments in research on L2 WTC. First, the article discusses the strengths and limitations of the major conceptualizations of L2 WTC, i.e. MacIntyre et al. pyramid model, Wen and Clement Chinese conceptualization, and Kang's situational model of L2 WTC. Second, the article presents the basic features of the complex dynamic systems theory (CDST) and discusses how it serves as a meta-theory with immense explanatory power to encompass the complex, dynamic and non-linear behaviour of L2 WTC. Finally, corresponding to a CDST construal of L2 WTC, the paper discusses some of the methodological developments and possible directions for future research. The article aims to contribute to language teachers' and teacher educators' awareness of the complex and dynamic nature of L2 WTC and provide future researchers with an alternative theoretical framework and corresponding methods to study L2 WTC.