Research on model-based reasoning in technology tends to focus on the informational role of models. That is, it concentrates on the use of models as a source of information about how to solve a given design problem. However, besides their informational role, models can also serve an ideological role. That is, models can provide affirmation of the moral correctness of a design program. In this article, the role of models within three design programs is examined. These programs are Gothic Revivalism, Modernist architecture, and industrial design in the early twentieth Century. In each case, the ideology of the program is sketched and the role of models within them is discussed. Through this exercise, we see that models for design are selected not only for their help in solving design problems but also for their service in reflecting and reinforcing the worldview of the designer.