Multinational corporations (MNCs) have increasingly sourced knowledge across borders, and foreign subsidiaries operations have played a critical role in MNC international knowledge sourcing strategies. The growing responsibility of foreign subsidiaries has paralleled an interest on the geography of this phenomenon by international business and international management scholars. In this chapter, we review this research. In addition, based on recent research in economics and management drawing on economic geography and innovation studies, we highlight possible avenues of research to enrich our understanding of the geographical aspects of international knowledge sourcing. In particular, we suggest three lines of research opportunities. A first opportunity relates to the explicit consideration of distance and border effects. A further research opportunity arises from investigating the geographical distance of heterogeneous host country knowledge sources from the foreign subsidiary. A final research opportunity we discuss is about the contribution of heterogeneous host country knowledge sources to the variety of knowledge developed by the foreign subsidiary.