This article discusses the phenomenon of task-based language teaching (TBLT) in instructed additional language settings. It begins from the premise that, despite considerable theoretical and empirical support, TBLT remains a contested endeavour. Critics of TBLT argue that, particularly with regard to time-limited foreign language instructional contexts, TBLT's learner-centred and experiential approach to second language acquisition fails to provide an adequately structured environment that allows for sufficient exposure to frequent language, and processing and practising of grammatical form. At the same time, differences emerge between how TBLT is conceptualised in theory and how TBLT is operationalised practically in many additional language classrooms. These realities signal the need to look at the interface between theory, research and practice. The article considers what current research into TBLT has not succeeded in getting through to classrooms, what has succeeded in getting through reasonably well, and what has been over-applied. It is concluded that the under- and over-application of theory and research in practice highlight the difficulty in identifying exactly what TBLT is or should be in instructed contexts. The article proposes a way forward to strengthen the effectiveness of the TBLT endeavour.