Robust conceptual frameworks are essential to building academic knowledge. Theory development involves high-quality conceptualization that integrates and builds on existing knowledge, possibly using a multi-disciplinary approach. Further, especially in an applied research area such as business-to-business marketing, the emerging theory will have meaningful implications for managerial decision-makers. Insightful conceptual framework development advances theory substantially, not incrementally. Theoretical development can be either purely conceptual or based on empirical data. Nevertheless, there are comparatively few guidelines for the process of conceptual framework development. This chapter discusses pathways to developing conceptual frameworks to support academic research, with emphasis on business-to-business marketing research. As guidelines and conventions are available for data-driven approaches such as grounded theory, we focus on theorizing processes in which existing theory plays a pivotal role.