Many influential theories of organization rest on an analogical foundation: we think of the organization as if it were a governance structure, a nexus of contracts, a social network, or an information processing system. We may invoke an analogy simply to express an idea, but analogy use may also constitute a key part of a theoretical explanation and an argument. In this latter, explanatory use, we not only think but also reason by analogy. But if analogy use constitutes reasoning, it must also be critically evaluated as such. In this paper, we first combine ideas from the literature on argumentation and cognitive science to examine how analogies are used in organization theory. We then construct a framework to guide the evaluation of reasoning by analogy. Finally, we show that by understanding how analogies are used and evaluated we can also gain an understanding of how theories progress.