["TESOL Quarterly, EarlyView. ", "\nAbstract\nThis article reviews the influence of conversation analysis (CA) in TESOL research over the previous six decades. Grounded in CA's ethnomethodological foundations, I trace its progression from sociology into second language education in four developmental phases: (1) early conceptual influences (1970s–1980s), (2) emerging methodological interest and integration (1990s–early 2000s), (3) methodological refinement and establishment (mid‐2000s–mid‐2010s), and (4) sophistication and diversification (mid‐2010s–present). With particular focus on work published in TESOL Quarterly, this review highlights how CA has revealed the collaborative nature of language learning within and outside the classroom and sharpened understandings of interactional competence. CA's distinctive contribution to TESOL lies in its capacity to explicate the social foundations of language learning and teaching through empirically grounded, participant‐oriented analysis of interactions that span diverse learning ecologies, with increasing attention to emergent digital and multimodal environments.\n"]