Informed and inspired by neo-Vygotskian theory, this article outlines a study exploiting a contemporary conceptualization of Wells's (2002) joint activity system model as an exploratory framework for examining and depicting the social-cultural-historical contradictions in second-language (L2) learners' joint activity. The participants were a pair of advanced-level Japanese English-as-a-foreign-language learners, and their joint activity was the focus of analysis in a lesson they completed together, which was based on a pedagogical cycle aimed at developing their metacognition of L2 listening. To address the various dimensions depicted in the joint activity system model utilized, data from written journals, interviews, and dialogue were analyzed. The analysis explored the learners' motives, history and beliefs, pair work, goals, and pattern of interaction in order to identify the social-cultural-historical contradictions shaping their development of metacognition of L2 listening. The joint activity system analysis illustrated that a number of social-cultural-historical contradictions were both driving and inhibiting learners' metacognitive development.