Although alliances often create valuable learning opportunities, the exploitation of the opportunities is a difficult, frustrating, and often misunderstood process. More often than not, firms learn little from their alliance partners. This article examines General Motors (GM) and its exploitation of the learning opportunity created by NUMMI, its California-based alliance with Toyota. Over the past few decades, GM has steadily and significantly improved its quality and productivity relative to its main rivals. A key factor in this improvement has been knowledge transferred from Toyota to NUMMI and NUMMI to GM. This article describes how GM transferred the "sticky" knowledge of NUMMI to the initially skeptical GM manufacturing community. The learning mechanisms employed included managerial assignments to NUMMI, visits and tours to NUMMI, a technical liaison office for managing learning activities, leadership commitment and involvement in the learning process, and a learning network to articulate and spread the knowledge.