This paper proposes to explore the theory of affordances in the light of cultural historical activity theory (CHAT) to study affordances in complex Computer-Assisted Language Learning (CALL) environments. The term 'affordance' designates an action possibility that is offered by an environment or an object to an actor in the environment either "for good or ill" (Gibson, 1979). It depends not only on the inherent characteristics of the environment but also on the users' perception and action capabilities. CALL affordances are said to be a unique combination of social, educational, linguistic, and technological affordances (Blin, 2016a). However, there is limited research to date that looks at affordances from an ecological perspective linking the micro moment-to-moment interaction levels with the macro level within which they are embedded in educational contexts (Blin, 2016a). This paper explores the analytical tools of CHAT (Leontyev, 1978; Engeström, 1987) as particularly suitable to investigate affordances at the macro, meso and micro levels of technology-mediated sociocultural educational contexts in CALL.