In this paper, we use an organizational learning perspective to examine the extent of internationalization of young, technology-based firms. We develop hypotheses on the impact of the firm‟s knowledge-base at founding, experiential learning, and interorganizational learning on internationalization, and use data on 114 young, technology-based firms in Flanders to test our hypotheses. The results show that both experiential learning and interorganizational learning have a significant, positive impact on the extent of internationalization. Further, by examining the interaction of these two types of learning, we find that learning from key partners may substitute for experiential learning; i.e., young, technology-based firms benefit more from interorganizational learning when their level of experiential learning is low. These results highlight the important role that key partners play in shaping the internationalization of young, technology-based firms and contribute to theory development in the fields of internationalization and organizational learning.