Companies increasingly make use of external knowledge exploitation, i.e. the commercialization of knowledge assets, although they often perceive considerable difficulties in managing external commercialization tasks. These difficulties are partly due to the imperfections in the markets for knowledge, which may be mastered by adequate management, as examples of various well-known companies show. In combination, these facts point to the need for research into external knowledge exploitation. A thorough analysis of past research confirms this need and shows that the existing literature is highly fragmented. By integrating the main findings of the different research streams, a detailed overview of the literature on external knowledge exploitation is established. The key characteristics of externally leveraging knowledge assets are presented, and a research agenda is set up.