An assessment of spatial planning practice at the end of the 20th century suggested that the adoption and use of geoinformation tools (geographic information and spatial modeling systems) are far from widespread and far from being effectively integrated into the planning process (Stillwell et al, 1999). From the assessment it may be concluded that many planners now have access to the geodata and meta-geoinformation facilities of their organizations, and many are proficient in using their geoinformation tools to perform spatial queries and to generate thematic maps. Progress towards the use of these tools beyond these basic activities to help solve key planning problems through more sophisticated analysis, however, remains very limited (Stillwell et al, 1999). Geoinformation tools appear to be seldom used for those tasks that are unique to planning, such as visioning, storytelling, forecasting, analysis, sketching, and evaluation (Couclelis, 2003;Klosterman, 1997).Studies to explain the shortfall in the adoption of geoinformation tools have often taken a broad, systems-analytical perspective, suggesting not only reasons of a technical nature, but also human, organizational, and institutional factors. Alleged reasons are that most current tools are far too generic, complex, and inflexible, incompatible with most planning tasks, oriented towards technology rather than problems, and too focused on strict rationality (Batty, 2003;Bishop, 1998 Abstract. Research on planning support systems (PSS) is characterized by a strong emphasis on the supply side, whereas little research has been undertaken on the successes and failures in the adoption of PSS within the planning community (demand side). What becomes clear from the existing research is that usage is not widespread. In this paper we aim to find the main bottlenecks blocking the widespread use of PSS in spatial planning. To achieve this, a global online survey was conducted in which almost 100 PSS experts participated and for which a theoretical framework from the field of business studies served as a basis. The results show that a multitude of factors cause the underutilization of PSS, their characteristics being human, organizational and institutional, as well as technical. In particular, the lack of awareness of and experience with PSS, alongside the relative lack of recognition of the value of PSS within the spatial planning community, tend to block widespread usage and adoption of PSS in planning practice. On this basis, we offer recommendations for the enhancement of PSS adoption, namely to disseminate more profoundly information and knowledge about the existence and benefits of PSS within the spatial planning community. Real-world example projects and in-depth research on potential benefits of PSS application in planning practice will be crucial in this. DOI:10.1068/a3712 ô Also Nexpri, Utrecht University. and Stillwell, 2003a;Harris and Batty, 1993;Innes and Simpson, 1993;Klosterman and Landis, 1988;Nedovic-Budic, 1998; Scholten and Stillwell, 1990;Sheppa...