This article traces the intellectual roots and developments of the notion of competence in second language (L2) teaching and research. Since L2 teaching and research invariably concern competence of some sort (linguistic, communicative, interactional, or otherwise), there have been countless attempts to define competence from diverse theoretical perspectives, resulting in a plethora of definitions as well as debates, confusions, and tensions. As global mobility and technological advancements prompt us to question traditional assumptions in our field, it is high time to take stock of how the notion of competence has been dealt with in L2 teaching and research. With a particular focus on interactional discourse, this short article offers a glimpse into the conceptual diversity regarding competence and facilitate further exploration of how it may be researched and fostered in view of modern-day complexities. The article concludes with a discussion of pedagogical implications and controversies.