The prevalence of non-spatial approaches and physical determinism in the management of spatial changes and solving urban problems in the Tehran Metropolitan has led to a situation in which urban plans such as Tehran’s Master Plan (2007) and the 22 District plans of Tehran metropolitan (2012) have been less than successful in fulfilling expectations regarding the urban spatial system and uncertainties affecting such systems. Dealing with urban problems and uncertainties affecting strategic decision-making including those associated with the planning environment, the guiding values of the planning process, and finally those associated with the decisions made by other stakeholders through strategic spatial planning in an era characterized by an accumulation of knowledge and information, would require knowledge management. Urban Planning problems due to spatial and political nature of planning will not fit into traditional information systems. This fact shifts the emphasis and application of information systems and “knowledge-management” in urban planning from a mere technical to a broader context suitable for the rationale of a strategic spatial planning. Knowledge-management as a set of procedures, infrastructures, technical and managerial tools is a designed process towards creating, sharing and leveraging information and knowledge within and around organizations. The absence of an urban knowledge management system has increased the dynamism and complexity of urban problems. In fact, creation of such a system as an important component of the efficiency of any urban planning system has been largely overlooked in both planning research and practice. This paper is an attempt to answer two basic questions: first, what challenges does Tehran’s urban planning system face from the perspective of a knowledge-based strategic spatial planning system based on the principles of knowledge management? And second, what is the appropriate management model to be applied in Tehran’s urban planning system? Dealing with these two questions will help us achieve the main purpose of this paper: enhancing Tehran’s urban planning system through application of the principles of strategic spatial planning and knowledge management (knowledge-based strategic spatial planning). To this end, a qualitative research approach based on a two-stage descriptive-analytic and analytic-prescriptive process has been adopted. Systematic review of the research literature constitutes the first stage of this methodology. The second stage deals with "progressive abstraction problem-finding", focus group method, content analysis and the “conceptual suitability”. Our findings indicate that knowledge management enhances the efficiency of Tehran’s urban planning system in the framework of the strategic spatial planning approach through the generation and application of all types of knowledge, providing the context for learning from knowledge, creating a flexible knowledge base, promoting knowledge exchange, raising public awareness and the promotion of a knowledge application culture. However, the absence of belief in knowledge management and strategic thinking within the formal institutional structures (such as the legal system, governance and organizations) and informal institutions (such as culture, history and public beliefs) constitutes the main challenge facing Tehran’s urban planning system.