How do experts assess the quality of fine art museums? While there is a well-developed body of sociological knowledge on evaluation and classification processes, there has been little work to treat museums as an object of inquiry. Yet guidance from the multidisciplinary museum literature only offers an undersocialized view of these organizations. I argue that museums offer a rich opportunity to study how classification, cognition, and interaction unfold in a developed field, because valuation processes are related to aesthetics in a particularly rich way. A diverse group of museum professionals offer their perspectives on organizational quality. The study finds that art professionals make an extensive range of symbolic distinctions in their understanding of quality, some of which are shared. How individuals compare museums to one another illuminates implicit status hierarchies and classification biases in cognition. A unique contribution of this study lies in the explication of different kinds of interactions between museums. In doing so, this study adds depth to prior work on evaluation, and breadth to research on inter-organization relationships.