This paper sets out to develop a robust theory in a largely atheoretical field of study. The increasing importance of entrepreneurship in delivering the "Third Mission" calls for an enhanced understanding of the university entrepreneurship phenomenon, not solely as a subject of academic interest but also to guide the work of practitioners in the field. By adopting a systematic approach to theory building, a model has been derived by integrating theoretical conjectures from corporate entrepreneurship and university entrepreneurship literature. The integrated theoretical model developed locates university entrepreneurship as an organizational process in an entrepreneurial system depicted as an input-process-output model. Characterizations of the entrepreneurial process and system conditions that would justify an institution being classified as an entrepreneurial university are proposed; and the inter-relationships between the system, the system components and moderators of the effectiveness of the system are outlined. The integrated theory described in this paper contributes to academic knowledge and understanding of university entrepreneurship and, equally importantly, presents a model and relationships that can be useful to third-stream practitioners and senior institutional managers. The paper is among the first to derive systematically a theoretical construct for creating and sustaining university entrepreneurship. It should help to stimulate a debate that might add clarity to an increasingly important field of organizational development. (Contains 1 figure.)