With the growing penetration of IT and its critical role within organizations, the number of requests for IT services and solutions is steadily increasing. However, many companies lack a consolidated view of all these requests or demands. They also struggle to track and report on the conversion of demands into IT solutions. Given the importance of managing demands for effective IT landscape development and for satisfying business users, our research aims at developing a design theory for an end-to-end demand management process. It is based on an extensive action design research study involving experts from 13 companies. The main contribution is a set of seven principles that guide the effective design of IT demand management. By focusing on the process from the emergent demand to the ready-to-use solution, our work closes a gap in existing research which is fragmented into requirements engineering, project portfolio management, and IT governance streams.