Although many diverse areas employ simulation models, no agreed-upon taxonomy has been developed to categorize and structure simulation models for all science and engineering disciplines. The discipline of simulation is often splintered due to this lack of structure, with ad hoc model classes such as ‘discrete event,’ ‘continuous’ and ‘combined.’ These classes most often reflect the method of execution used on a model rather than the design structure of the model. We present a uniform model design taxonomy whose categories are inspired from categories in programming language principles within the field of computer science. The taxonomy includes a set of primitive model types (conceptual, declarative, functional, constraint, spatial) and a way of integrating primitive model types together (multimodeling). These model types are discussed using a single application: a robot server for an assembly line. We have found this taxonomy enables simulators to more easily define and categorize their models as well as to understand how model types from seemingly disparate application areas are interrelated.