This state-of-the-art paper foregrounds mixed-methods research (MMR) in language teaching and learning by discussing and critically reviewing issues related to this newly developed research paradigm. The paper has six sections. The first provides a context for the discussion of MMR through an introductory review of quantitative and qualitative paradigms. In the second section we discuss the nature and scope of MMR, its underlying principles, and its techniques and procedures. In the third section we discuss trends in MMR in language teaching and learning, and review 40 published papers in 30 journals related to this field, covering one decade (2002-2011). Issues and challenges facing MMR and its researchers are discussed in the fourth section, while in the fifth we discuss the significance of replicating MMR studies in language teaching and learning. Finally, we conclude by presenting prospects and avenues for further developing mixed-methods research.