The authors present a framework for the analysis of models which have been designed for, or used in, urban physical and economic planning. The models have been distinguished by their basic characteristics, rather than on the basis of their applications. Four basic characteristics are identified: (1) the subject of the model; (2) its function; (3) its underlying theory; and (4) its method. Besides providing a conceptual framework for the analysis and development of urban planning models, this conceptual scheme serves as the basis of a classification scheme which allows the study and comparison of existing models. Such a system is presented as an illustration of the process of model analysis using this conceptual framework.