<p>Co-agency, as an emerging phenomenon at the intersection of individual agencies, plays a critical role in advancing meaning-making processes while simultaneously developing and expanding individual agency in online collaborative learning. Despite its significance, the development and expansion of co-agency remain under-researched, as much of the existing scholarship emphasises individual agency—often defined as the capacity to navigate resources and assume responsibility for one’s learning in online environments. This study examines how co-agency evolves and how the intersection between individual and co-agency influences online collaborative learning processes. Grounded in cultural-historical theory and employing qualitative interaction analysis, the findings demonstrate that co-agency emerges through the intersections of individual agencies in collaborative meaning-making processes. A symbiotic relationship between the two forms of agency is evident: the more actively students enact individual agency by contributing experiences and anecdotes, the deeper the interactions become, thereby nurturing co-agency. The study concludes by outlining key pedagogical and theoretical implications of these findings.</p>