What is the impact of specific knowledge-transfer processes on the level of shared knowledge and, in turn, on outsourcing performance in outsourcing relationships? Drawing on a series of case studies covering IT providers and banks, we investigate several applied knowledge-transfer processes dedicated to the transfer of explicit or tacit knowledge between outsourcing banks and their providers. We examine the differential influence of various types of knowledge transfer on shared knowledge between the parties and on the resulting outsourcing performance. Results depict the differential impact of various knowledge-transfer processes dedicated to the transfer of explicit, or tacit knowledge, respectively, on the development of shared knowledge. Interestingly, the combination of both knowledge-transfer processes dedicated to the transfer of explicit knowledge and those dedicated to the transfer of tacit knowledge proves to be most effective.