The literature on individual and organizational learning in alliances has extensively focused on the transfer of knowledge. In contrast, the mutual creation of inter-organizational knowledge has been neglected so far. First, this paper adopts a social-cognitive view on knowledge creation in the relational sphere. Second, it contrasts two distinct styles of alliance management and links those to genuine knowledge creation. After discussing basic concepts and theory that address the management of an alliances process and relational learning from a mental models perspective, we derive a structural equation model which is tested in a study of 222 alliances in the new media industry. We find effects through two distinct styles of alliance project management on two configurations of relational learning: absorption and autopoiesis.