With the intention of defining an initial research agenda for discipline-specific factors in the usability of e-learning websites, this article focuses on the example of foreign language learning. First, general notions and concepts of usability are analyzed, and the term "pedagogical usability" is proposed as a means of focusing on the close relationship between usability and pedagogical design. Then, to address the key issue of whether there are aspects of pedagogical usability that are discipline-specific, the article examines how language learning and teaching, in particular Technology Enhanced Language Learning (TELL), has approached usability when developing technology-enhanced learning materials. Three elements of a research agenda are identified: (a) pedagogical usability, (b) intercultural usability, and (c) website evaluation. In conclusion, it is suggested that, just as language learning websites may require a discipline-specific approach, other disciplines' pedagogical usability may also need to be considered in relation to the specific requirements of the discipline, and that a debate around these issues is timely. (Contains 2 figures and 2 tables.)