The fields of spatial planning, geographical information systems (GIS), and information and communication technology (ICT) are all developing at their own pace and in different directions, thereby obstructing the widespread acceptance of GIS as an integral part of planning practice. In this paper I take a closer look at their divergence and outline the role that a planning support system (PSS) can play in bridging this growing gap. I consider the benefits of participatory planning and show how my prototype of a PSS can contribute to its success. To that end, the functionality of this PSS is described in the context of the initial experience with its application in a diversity of planning circumstances. Some conclusions are then drawn on how a PSS can overcome some of the barriers to GIS support within planning practice.