The purpose of this research is twofold: to explore the complexity of spatial plan preparation and implementation in Ghana using Kumasi as a case study; and second, to examine the contradictions of spatial plans and ‘actual development’ occurring in Kumasi. Using social science research methods (semi-structured interviews) and physical survey (land use plans), findings indicate that spatial planning in Kumasi is a bureaucratic process hijacked by urban planning agencies with limited involvement of urban residents. As a result, urban development is considerably influenced by spontaneous informal development patterns (i.e. self-organization). This phenomenon of self-organization is expressed in a context of uncertainty created by weak spatial planning system which encourages haphazard development. Regrettably, in Kumasi, self-organization is often overlooked by spatial planning agencies as they focused on rigid and exclusionary spatial plans. This paper advocates consideration and integration of self-organization processes in spatial planning efforts to respond adequately to the urban development challenges confronting Kumasi.