Mixed-methods research (MMR), as an inter-discourse (quantitative and qualitative) methodology, can provide applied linguistics researchers the opportunity to draw on and integrate the strengths of the two research methodological approaches in favour of making more rigorous inferences about research problems. In this article, the argument is made that the methodologically pluralistic characteristic of MMR is in line with the interdisciplinary nature of applied linguistics, and, in fact, that MMR enables researchers to investigate more complex research issues usually not possible with purely quantitative or qualitative methods. Three categories of MMR studies are discussed, namely, 'eclectic', 'principled eclectic', and 'innovative'. It is argued that in 'innovative' MMR studies, researchers treat MMR as a holistic 'methodology' and not a combination of separate 'methods' by including different epistemic perspectives in their conceptualization of the research problem. This is illustrated by presenting a recent epistemological discussion in applied linguistics. From a methodological perspective, two realizations of MMR are presented: mixed-methods grounded theory and mixed-methods phenomenological research which provide accounts for how a pluralistic conceptualization of research problems can be translated into 'innovative' mixed-methods as possible cases of innovative mixed-methods research (IMMR).