This article investigates research approaches used in traditional classroom-based interaction studies for identifying a suitable research method for studies in three-dimensional virtual learning environments (3DVLEs). As opportunities for language learning and teaching in virtual worlds emerge, so too do new research questions. An understanding of research design benefts and limitations is timely for those exploring how interaction occurs between users, and users and the virtual space, and how these interactions make sense within a broader theoretical framework. As a frst step, the article describes the types of interaction that are signifcant to classroom-based research studies, such as learner--learner. This is followed by a historical overview of research approaches and methods used in interaction studies, from early quantitative, to descriptive and qualitative, to mixed-method approaches. Following this overview, the author critically surveys research approaches, methods, analytical tools, and data collection techniques used in physical and virtual second language classroom interaction studies. The article concludes by highlighting the implications and research considerations for the design of new research studies in 3DVLEs.